Random unit thoughts:
Short Range Turret III feels both too expensive for it's cost, and possibly in the wrong place in the tech tree. Laser turrents are cheaper (half the price!), have more health, do 50% more damage over time (and do it in smaller chunks so better to minimize "overkill" for swarms of smaller ships). The only reason to use SRT III seems to be that it gives you more turrets since the only benefit from II is double the damage at a massive increase in cost.
Maybe if the SRT series scaled up in damage/health like the MLRS Turrets do, it would be a bit more of a reason to purchase them?
As to the place in the tech tree, it would be nice if they were useful as an alternative to Laser Turrets rather then having the Lasers depend on them. It would mean the Lightning Turrets aren't so incredibly deep in the tree (I don't think I've ever had the chance to research them
), and would be a good test of whether the balance of them is "right" too whether you continue to research the shell based tree, or swap to the laser/electicity based tree. And of course even if you had a preference, it would change depending upon what the enemies are throwing at you due to shell-resistance and the like.
On a similar thought, I also never seem to use the Tractor Beam Turret II, except if I run out of Turret I's (which almost never happens). It's possibly more "must have" when in higher AIs, or multiplayer when the AIs start tossing lots more ships at you in wormhole attacks but singleplayer/AI7 it doesn't seem to be needed, even when I'm playing against enthusiastic planet attacker AIs and increased AI resources.
Maybe if it slowed normally "immune to tractor beam" ships (non starship types) to 50% speed whilst in range? It would make it a "must get" for when being attacked by a raider or the various melee equipped AIs, like getting the Tachyon Beam Emitter is a must-get for Stealth equipped AIs.
Advanced Factories and Type IV teleporting ships don't really play nice together since the advanced factory is fixed, and the ships can't move through wormholes. Sure the Transport Ship can be used to partially minimise the inconvenience, but it's a pain to have to shuffle things around like that, and an expensive knowledge upgrade (and would essentially need to be factored into the "desirability" of the teleporting ships when you pick them at the start, or you get them when in game; I still feel like the AI is taunting me when I get a teleporting ship from an Advanced Research Station
).
Maybe if the Advanced Factory could be moved slowly like the Advanced Research Station. It would mean you could actually wander it around a little, but you'd certainly never want it directly on the front lines since it's so insanely fragile. Plus it only produces Tech IV ships, so you still don't have the ability to massively reinforce right near the front line easily like you would if you had mobile Tech I-III ship builders.
Mobile Repair Station: Cool concept, but it feels way too fiddly using it in practice.
If the ships you build were all "magnetic" and kept themselves within a certain range of the station, except when flying out to grab things and return them, it would be much more convenient moving it around, especially between planets (so ships "built" from a particular station would always be "attached" to that station, if the station dies, they go poof as well presumably; would make it more inconvenient and expensive and mean you have to be a little more careful with them).
Advanced Warp Sensors seem to be a bit on the "why bother?" side as well. I used them a lot when I first started playing, especially on the easier difficulty levels, but once you get to a bit higher skilled they just don't seem to be all that useful. Again, possibly I'm just not playing multiplayer/higher-AI where the waves of ships are huge enough to matter to micro a stack of ships around, but generally my defenses are enough that I can just have a bunch of ships on roaming-attack and they'll swat down whatever was throwing itself against me whether I know the wormhole or not. And if they can't it's usually because the attack was way too powerful to defend against with their small force anyway (usually a couple of starships).
And on an unrelated note (and strangely enough something I only just noticed... yeah, quick on the uptake I am
), there's a distinct lack of MLRS III to match up with SRT III.
I guess the Missile Turret was part of that upgrade chain previously so that's why it never existed or something.