Played for a few hours getting a chunk into the game. Point thoughts:
(1) Agreed that turrets aren't really ever sexy unlocks. It's hard for new players to tell exactly how much they need per AI Progress, and they always sit useless otherwise. I also don't think taking the detailed placement from AIWC is a really useful idea, since it's not that beneficial of a timesink.
(2) One of the reasons I think players are complaining that the turrets are too weak is, I think, that the sequel seems to work differently on ship numbers. At about 90 AIP or so, the incoming wave is a flood of tech I, which overwhelms a light choke (25% cap of all 100 cap turrets plus 50 tractors). The mobile fleet then takes 10 minutes to get there.
(3) Briefly looking at the brainstorm thread, the item I would desire the most would be "Individual fleetship constructors instead have caps, and the fleetships from them have a permanent link to them." It's easier for me to map this setup to the armies concept in Ashes of the Singularity, and essentially the game becomes more carrier-based (and somewhat closer to Wing Commander lore where all fleetships map to the WC fighters).
(3B) However, this probably means players will need to find an additional flagship ASAP, since it doubles their offensive fleet-power. If players start with more and a smaller cap, this would smooth out some of the initial growth. I would personally put in 3 for strategic choice. Since document says only groups 2-8 are available, perhaps make some derelict flagships upgrades for the weak prototype?
(4) Perhaps, fortresses would have its own set of mobile power-using assets. Power distribution nodes can be militarised to have its own static "turrets". Don't allow players to put turrets on the map so they don't waste their time micromanaging and getting frustrated from non-reward?
(5) Read the hacking document. Might work, but would suggest to be more impactful on the battle to remind players they exist. E.g. add the following: 1. disable wormhole entry/exit. 2. shutdown turrets/mass drivers/ion cannons.
Good luck.