I'm sure I'm like many in having been playing Sins since it's release (and since the original early access). This looks like it's going to be a great resurgence for SOASE. After playing my first complete campaign in the technical preview, here's some of my thoughts. There's some bugs, some design iffyness, and just some general musings.

UI/GRAPHICS

• Garrison needs a X / max display
• Icons blend together to much
• Missiles are ominous to see a raft of them coming at you, but otherwise useless as icons
• Needs some indication of planet speed. Maybe length of the pointer?
• Need to be able to cancel construction of surface structures from the display of surface structures
• Need to be able to scroll through a planet's construction queue
• Planet bombardment needs some more visual oomph. It's hard to even tell your ships are bombarding.
• I think keeping the hot keys from sins 1 would be a better choice. Particularly ones like "s" for stop, which is now "r", and makes no sense.
• The icons need more definition.

FEATURE FEEDBACK

• Diplomacy doesn't work (or at least no one accepts anything) - May just be me not understanding
• Disappearing phase lanes - This is cool, but there needs to be a more obvious sign that they are about to disappear. The flashing effect seems perfect for this, but it triggers when you can no longer use the lane.
• Research UI needs a better interface. Telling what is at what level of research is damn near impossible
• The Akkan's abilities need some work. There is nearly no reason to have multiple akkans in a fleet; certainly no more than 2. They've only got one combat ability, and unless it stacks from multiple uses, you don't need several of them.

MISC BUGS

• Kol beam frequently would not render.
• The dragging of ships to the sidebar is a bit glitchy

MUSINGS

• Garrisons have the potential to really make offense difficult by stacking several garrisoned planets together and moving their garrisons en masse to defend a planet. On the other hand, they could really give the upper hand in an attack if you wind up with several garrisoned planets phase linked to an enemy's planet. As someone else on the forums, this seems very OP at the moment. On the other hand, when we get starbases and titans in the game, the power scale is likely to shift quite a bit.
• The unit scale seems off. Personally I'd like to see everything knocked down by ~50% +/- a bit per ship class
• NEED an actual empire management sidebar and true fleet pinning. If we could set a fleet to stay at a given mix of forces and replenish itself from the closest factories, that would be amazing.
• The uniform jumping logic seems to be VASTLY improved from SOASE
• Being able to reorder a build queue on the fly is a great addition.
• Something I always wished SOASE had was the ability to give strikecraft targets from their carriers instead of needing to select all the bombers to do a run on a given target.
• Feel like moons need to orbit faster
• End game feels like it's going to be stacks of capitals since there's no limit on them now (at least if you have the resources to craft exotics) and a capital seems like it's more cost effective than any cruiser/frigate ship that does the same combat role; plus they have abilities and equipment.
• Late game, minor factions would be more useful bombing their planets and taking over.
• It's surprisingly easy to wind up with forces cut off from your main empire
• Garrisons should have some AI settings. Something along the lines of Turtle - Balanced - Rush

Here's looking forward to the progress of the technical preview and many future updates adding features and fixing bugs!