I'd like to see a few new Citizen types - such as Doctor or a Bishop.

Tied in with this, insert some random events such as a plague/virus that either your civilization needs one to combat the illness or have to barter/buy/steal medicine from another civilization. And the Bishop could be used to help morale on your planets (although the Celebrity is already there for that, right? So maybe scratch that idea.)

More promotion options for Spies - being able to spread propaganda amongst your own people in times of war, for instance. Which helps keep morale up.

Which makes me think of a further trade "good" - but only between allies/close friends. Being able to loan Citizens for a certain period - you ask for a Worker from the Terran at, say, 1 antimatter and 50bc a turn for an agreed time as set out by the civilization the Citizen is being loaned from. I don't think making the temporary loan a permanent buy is a good idea because that might be a bit too cheesy and exploitable, though.

Asked several times before, I would like to have race´s favourite weapon/defense combo in the surveillance screen, when spying on them.

Also delivering the rework of minor civilisation in some unique way would be nice  

I would like to see more focus on "balanced" conquest and diplomacy.

In Games like Europa Universalis or Crusader Kings you can choose war goals and in the aftermath claim a price for your victory. That would help to prevent whole civilizations from being extinguished. I always found it a bit cheesy to weaken all my enemys by taking them planet by planet (the whole game). They never give up so i will be forced to conquer them in the end. On the other hand they will never rise to power again. I like the idea of a living universe even with weaker civilizations. In an endless game mode the should also survive because they maybe have special bonus (for being weak or small or even depending on your traits), while the badguys receive mali for conquering or owning large parts of the universe. Maybe whole alliances form to support a benevolent race from being conquered.

This would a great playhouse for diplomacy, United Planets and Galactic Events (for example: Revolution for a supressed/conquered species (maybe even supported by foreign agents)). Therefore planets of other civilizations should only be annexed like in MOO). A new quest/event system may be useful for forming alliances as well (supporting the superweapon, dismantle existing fleets, help to defeat a huge monster, lure it to your enemys territory, Propaganda during war to push/deafeat morale...)

Diplomacy itself needs a little revamp. The AI should recognize my ranks and abilities, friendship should be more valued and treachery punished by all known partners. Also new techs and abilites help to play more charming like a tribble even to a drengin/Klingon

All in whole i could imagine a more stable universe. Not that i oppose war and conquest but my last tries to conquer a gigantic universe had ended in aborting the games completly bored. So maybe winning the game even as a smaller civilization sounds appealing to me.

Much of these ideas could be realised at this moment but depend on much ai rework and modding. So why not in a new DLC. I would surely buy it

Some good feedback but it's pretty obvious you are focusing on large galaxies.  

Yes, it's interesting about the AI. I happen to agree with you that it is VERY important. But there was an interesting discussion regarding AI in the Civ6 forum a while back.

Basically some folks were bemoaning about how bad the AI is in Civ6. And then someone (probably correctly) pointed out that these days, most players don't really WANT to be challenged. They want to move their units around and make some decision and pretend it was a challenge, but in the end they just want to win. 

So putting in a challenging AI has become less and less of a priority (which is lucky for many game developers since they are creating complex games that their AIs couldn't play well anyways). So, one of the main 'selling points' of GC3 as a 4x game is it's AI and the continual improvement of it but unfortunately that is something that it's appearing that many players are not prioritizing. 

As far as what I would like see? I would like to see less radical swings in core game mechanics with each new iteration. Wheel/No Wheel/Square-root Pop production/One for one Pop production/Food is king/+1 buildings are king/etc etc. Each iteration tends to break the game econ and throw things out of balance and requires multiple balance passes to start to get it ‘right’ again. I haven’t played the latest opt-ins yet, but I felt that 2.6 put way too much production back into the game again. Ship costs mattered a lot less than earlier since most ships (early on at least) can be produced in a few turns anyways. So the granularity of production costs has greatly diminished again and building things no longer feels like an ‘accomplishment’. And I don’t bother with the smaller % increase boosts for Ship Production or whatnot anymore since it doesn’t seem to have much overall effect. I still build most ships quickly enough now not to worry about it.

Also, each major iteration requires ‘re-learning’ what to do again. This isn’t ‘strategy’ per se, it’s simply puzzling out the mechanics…again. So my preference on this front is pick a system and balance it out. I guess I was in the minority when it came to the square root population but I thought in its final iteration before switching back to one-to-one, it was in a pretty good place. I wanted pop, but I wanted buildings too. There were some buildings that were ‘too good’ (generally the ones that gave a flat bonus that was boosted by adjacency) that is easily fixed.

Finally, I would still like to see the early game be much less of a ‘race to colonize everything’. I tend to play mostly on Medium maps (and occasionally Large) but both play out mostly the same due to increased race density. I think the Administrators were an attempt to slow that down, but in practice it hasn’t changed at all. You mostly need to spend your opening cash on colony ships to grab whatever you can, whenever you can. Speaking of, why does everyone start with such a huge wad of cash? I think that is probably the biggest contributor to the ‘colony rush’.  

FWIW, I’m not a huge fan of scripts and scripted events because (as happens in Stellaris), once you’ve played through and seen them a few times, you just skip through them anyways. The ‘interesting’ in the game should come from the decision-making in the situations you run into, not scripted events IMO.

Anyways, it’s unfortunate that the Steam reviews are so poor and that people use that to axe-grind over mechanics changes (rather than a discussion forum). I think I have posted a review but I’ll make sure when I get home because while I didn’t greatly enjoy the mechanics the last time I played, I would definitely like to see development continue in hopes of it hitting a sweet spot again.

The game definitely plays faster without the wheel. The required use of resources is more challenging. Since 2.6, the AI now fleets up and is more of a challenge. Balance is pretty reasonable now on starbase/shipyard defenses. Good progress there.

The thing is, this a space game. Space is vast, and the emphasis in the game should be on maps sized "Large" or bigger. It's also a 4x game, and the exploration phase shouldn't be eliminated by turn 100. Smaller sizes are cute, but shouldn't be the focus of development. I know that it's a lot easier to play test a small map, but if that's all you do on a regular basis and then set AI strategies on that basis, it doesn't work as well for the larger map sizes. If you have to prioritize dev efforts, please do so for the bigger maps.

Specific things to fix.

1. As Uncle Joe noted, please stop changing the base values- you're good enough now, and it should be minor tweaks/consistency moving forward
2. Fix the AI for planet builds- still not recognizing special tiles for improvements very well. It does seem to group better
3. Fix the AI to use/consider alternate paths to achieve a goal.  For example, if the AI needs more science, it should be able to consider the options, not just one path like just spamming planets with science labs
   1. build more standard labs on many planets
   2. build a special science improvement, like an Brindle's, and put that next to the core
   3. build a base to harvest the science relics out there (and stack these, and research the precursor tree!)
   4. build more population
   5. conquer the guys who do have science planets, or at least, those planets.
4. Do a full pass on the tech trees to catch the regressions for bldg improvements; I should always see an increase if I build the next bldg version
   1. there are still some bldg paths where the first bldg is a fixed amount and then upgrades are only a percent increase; these should always keep the fixed and then add the percentage

New things

Not sure, you guys are pretty innovative about that. I have to say that while I certainly haven't exhausted the range of sandbox variations, a set of campaign missions for various races in a DLC would appeal to me.

The other two notes have nothing to do with galaxy size. And they are on point.

Scenarios: Perhaps it is along the lines of quest system, but scenarios or a scenario editor might be fun.  For instance, permanent alliance set at the start (good vs evil, 2v1, 3v1, 2v2, 3v3, etc.), different starting conditions (different number of starting planets, resources, technology, etc) so perhaps a single planet highly tech race versus the vastly more numerous lower tech race (becomes a competition between how fast the high tech race destroys, versus the low tech defending and outgrowing thru science and production).  

Some narrative for third age, or fourth, content would be nice, sortof like the "Last Big War" from MoO 2.   By then, you're already further along with your victory goals where there's no challenge left against the balkanized galaxy with your superior empire.

Sorry managed, that a bit.  I'd be interested in what you guys would like to see in a more detailed ground invasion.

1: The ideology system still stinks and is WAY too dependent on colonization events.  Ideology points should be tied into the influence system.

I'm amazed that after two major expansions the ideology system is still as primitive as it is.  It really needs to be tied into an existing system like influence generating buildings in the same way that the CIV series social policies are tied into culture generation.   I don't object to colonization events and other events as a means to augment your ideology points; but it shouldn't be the driving factor behind their creation.   I think influence point generation should be the main way that you earn ideology points where influence gives you neutral ideology points that add onto the ones made by your choices in colonization events with the neutral points being able to be spent on any branch (benevolent, pragmatic, malevolent) of the ideology system.

 2: More Planets should be locked behind colonizing tech in order to slow expansion.

 I feel like colonization spamming is still an issue that screws with the pacing of the game.  Has any consideration been given to expanding the concept of extreme worlds to slow expansion? Like initially all you could colonize would be planets that are a lot like your race's homeworld (Normal planets and breadbasket for carbon based, Aquatic planets for aquatic races, etc) and there are more tiers of colonization techs to unlock planets that at present can be colonized from the start (desert, thin atmosphere, etc).   This would slow the need for colony spamming early on and make you feel less cheated by the AI beating you to a world you wanted.

 3:  Extending your ships range should be tied into building shipyards, starports, and starbase modules in order to slow expansion .

 As it is I think that the limitations on ship range don't do enough to slow expansion.  Colonizing a planet or building a starbase on its own should only expand your ships range slightly, whereas building a shipyard and a starport on planets or resupply modules on starbases would be necessary to significantly extend a ships range.  This would likewise serve to slow the player and the AI's rate of expansion.

 4:  Give the player more control over generation of citizens by tying their generation into morale.

 I like the citizens; but I feel that just throwing one at the player every 10 turns is a pretty arbitrary way to dole them out.  I'd like to see their generation be tied into the morale system so that a high morale increases their generation while a low morale slows it.  Likewise I'd like to see more ways for the player to increase their rate of generation by building improvements.  I really like the buildings that let me train citizens later on in the game and I'd like to see that concept expanded.   This would also make the morale system more significant.   On a side note I'd like to see the morale boosting improvements on starbases make a return.

 5:  Espionage could use some work.

I'm not really thrilled with the way spies are deployed to planets.   Disabling an enemy building seems like a weak way to spend a citizen and having to use spies to remove enemy spies from your buildings is an annoyance to the player.   I'd prefer some sort of mission based system where I can send my spies to steal credits or tech, lower morale, or blow things up (buildings, ships, maybe even starbases) which takes time and has a variable risk of the spy being caught depending on the difficulty of the mission and the spy's skill; but doesn't expend the spy unless they get caught.

 6:  Minor Races (city states) should be expanded not removed.

 I was disappointed to see minor races being pushed to the sidelines with the recent updates.  I realize they weren't working very well in their current form; but I like the concept behind them and was hoping they'd be fixed and expanded not removed.   For an example of what I had in mind, I'd point at Star Trek:  Birth of the Federation a game that had a different system for interacting with minor races as opposed to major powers.   This system allowed you to form trading relationships, alliances and even convince the minor race to join your empire (if you don't choose to conquer them) and if you could get them on board it would allow you to build special improvements that only that minor race could build.   At the very least you could just give them all some rare resources to trade (nanites, techapods, etc.).

7:  Improve Military Starbases.

As is I can rarely see a reason to build a military starbase instead of an economic, cultural or mining starbase.   By default I think they should get a buff to their weapons defenses when they're first built.   I also think their default area of effect should be larger than the other starbases since the buff they give to ships is their main purpose with tech unlocking further expansions to military starbase area of effect in addition to the expansions that effect all starbases.

8: More things for constructors to build aside from starbases.

Roads: Not actual roads obviously; but an improvement that lets you travel faster along a set path like hypergate lanes or what not.  They can be built and destroyed at a set distance apart (10 tiles maybe) to greatly boost your ships rate of travel between them and would add an extra layer of strategy.

Minefields:  You build them in a tile and when an enemy passes through they inflict a set amount of damage relative to tech level and they drastically slow down the number of tiles an enemy can move in a turn.

Sensor Buoys:  I frequently find myself building ships just to station them to keep an eye on an area.  It would be nice if I could just build an improvement to do the job for me at a cheaper cost.

9: More things to Survey unlocked by tech advances.

Like the archeology sites in CIV 5 basically hidden goody huts that don't appear until you've unlocked the tech that makes them appear.  Maybe some of the dead planets could be scanned for research points or credits.  Salvage anomalies appearing after a battle should be more common and I'd like the events where I find random derelict ships in anomalies or get flung somewhere by a wormhole to make a return.

And this is the main reason for not radically changing the econ every major update...it throws everything out of whack until a few balance passes have happened and/or it's scrapped a whole new system is implemented.

As I said with the wheel-no wheel-back to wheel situation way back when...pick a system and stick with it. Most players don't want to back to square one multiple times in either knowing how to play or waiting for the inevitable balancing needs.