To answer your question:

Via Advent pressure on the opposing force with their corvettes and tier zero spam. A player under pressure will have a harder time getting a titan.  Also, since this will be hard to balance perfectly, keep the in the reserve a plan B for balance, to reduce advent titan costs. 

Check out my most recent corvette balance thread outlining unique uses for corvettes for the 3 factions here:

https://forums.sinsofasolarempire.com/421581

The gist of the post, advent get corvettes at tech level 1, the other races at tech level 3-4.

This could be tweaked, but this would give the advent opening game the Rush capability they need...the point is their opponents should work hard to protect themselves.  The advent should then be able to

A: win the rush if they can.

B: eco up with the free time.

Its a fine line, I honestly think that if the rush is overpowered then the developers should focus more on the early game rush defense capabilities of the vasari and TEC.

This fits with the advent's sin, wrath.

This also makes the advent playstyle a bit more unique. 

Perhaps, different factions of the TEC/vasari could have corvettes at different tech levels?  This would add a great degree of variation to the early playstyle as well, making each faction seem different.

Advent early game eco isn't going to be too bad if its got enough time to get some culture and some metal/crystal upgrades.  This will keep them competitive without having to rely on just one ship.  I've always been a big supporter of just moving the advent crystal research tree down one level so that advent don't need tech level 3 for crystal research..its debilitating to them and always has been.

Perfect balance in this area will be:

Long term rush fights turn against the advent, so there isn't much incentive for their rush to occur for too long.

Even with a small early feed the advent rush capability will have a hard time overcoming the Structural defenses of a competent player(reducing corvette damage to buildings..helps them from debilitating an opponent too much by killing crystal and metal at their HW...).

Players will have to use defensive structures to assist in a successful defense.  This will tie credits down to defensive structures so immediate advent counter attack is unfeasible, allowing the advent to build up a different type(s) of ship (even when resold, the vasari would be able to recoup more of this cash to go on offense thus making research on their racial tech more alluring to them).

Rushes are capable of ensuring that opposing capitals and such are somewhat locked down to defensive posture so they don't get sniped.

TEC/vasari, if/when they beat the rush back would be at a stalemate position where they can either get a stronger economy or advance on the advent (who now have a stronger economy).  The TEC, if they already had one lab and a few upgrades wouldn't have to play too much catchup with their extremely cheap economy research. 

Advent vs advent fights would be a viscous micro battle so that they retain an element of unique gameplay(which would get old if you are ALWAYS fighting intricate corvette micro battles with all the other non advent factions/races)

A buff to in game constructors enabling them to Respawn early and or avoid/absorb more damage before they are taken out.  See my post about this:

https://forums.sinsofasolarempire.com/421601

This is no single path to victory, there are many other variables, but overall this playstyle would be quite exciting for both sides as both players are trying their hardest to come out on top.  I would pretty much not play another game for another 2-3 years if the game was on "average" something akin to this.

I believe this game, if inherently set up to favor this sort of encounter, would greatly benefit.

I agree with a argument that titan research is currently too low down the tree.

It always seemed odd that the last phase of titan tech is at a lower tier than that for heavy cruisers, the very units that often make up the backbone of mid/late game fleets.

Titans were perceived by many (myself included) to be a faction's ultimate fleet breaking weapon, and as such, were expected to require high tier research.

Not unlike the tech requirements for super-weapons in the original version of SoaSE.

It's good to see such rational discussion of proposed changes, eg the economic side-effects that may affect the Advent.

I'm not sure what is the best path to improve the late-game economy of the Advent, maybe "Allure of the Unity" could be improved, or add a new tech that reduces the fall in allegiance vs distance from capital.

Eg: level 1: allegiance drop 10% -> 5% per phase jump, level 2 5% -> 3%.

That could greatly improve the economy of a large Advent empire, as less cash & resources would be lost to corruption on distant worlds.

im going to throw my vote in for boshimi336's idea to have Titans as Heavy Capital Ships so they are just another choice of ship type instead of super central game points or as boshimi336 put it 'I WIN THE GAME SHIPS IF I BLOW YOUR TITAN UP FIRST!'

That they carry over their XP and levels is more worrisome for me right now. I hope this is just a testing phase for the beta, and will be removed once the game is released.

I don't understand why the mods get this correctly, that is über ships LAST, but the development team gives us Titans before Kodaiks........

I've simply resigned myself to accepting the game as is, and comforting myself that I can mod it however I want later...

For better or worse, Rebellion is pretty much entirely focused on titans and capital ships now, which all other ship types fairly marginalized...I don't like this, but I also don't think it is going to change...

Sins is an entirely different game now, and SD is making an appeal to a different audience...

@ seleucia

Don't give up the fight! 

If the developers have an "us vs them" mentality then yes we aren't going to get anywhere, and this beta will be a complete farce.

It will be plainly clear if the devolopers do not actually increase titan tech requirements, something the community at large seems to agree with.  This would be a marketing failure at a profound level. 

@ warloklord

Adding tech requirements is the simplest way to achieve titan balance and to justify titan BUFFS.

I agree with your suggestions in that titan build times and credit cost should be increased.

I'd rather have awesomely powerful strong ships designed for anti fleet in the endgame...Just can't have this too early or you won't be seeing many fleets (aside from rushes) to begin with.

increasing the cost of titans and pushing their research back will only hurt SP and not MP since ppl on MP will get feed alot and still get Titans out rly fast

Titans need to be mid-game or later.  When we in the 7 Deadly Sins mod made "Titan" capitals that were available early, everyone just fast-teched to them and obliterated everyone's pitiful frigate fleets and easily won the game if their opponent didn't have a "Titan".  Our meta-game was extremely Titan-centric, just like Rebellion's.  We ended up moving them much later in the tech tree and giving them very expensive research prerequisites so it is now extremely expensive to get one out.  The TCA doesn't get their "Titans" until around 5 or 6 labs IIRC and the Empire needs 6 or 7 before they get their Executor, and even then the "Titans" make Rebellion Titans look inexpensive.  Our balance is much improved from making our "Titans" late-game fleet and planet smashers that bust open stalemates instead of them being early-game fleet smashers that end up forcing everyone to build a Titan or lose.

The Corvettes just need to be nerfed in order to make the game more balanced. They should either receive more damage from all sources, have their movement speeds reduced, or do less weapon damage. Or a little bit of all of these things I just mentioned.

i agree they need to come at later in the game but making them cost more and pushing tech back it not the way to go

maybe a timer where they can only start building after an 1 or something but idk how or if that would work

What game settings are you playing on?! On normal speed settings Titans ideally shouldn't come out until mid-late game which in a 6-8 hour game is between 3-4 hours ... ?