Tac battles was the only decent choice. I actually voted other. Because mostly i could care less about tac combat.
What I'd love to see :
1) over haul using population to fight invasions.
a) Use soldiers that must be paid, and trained, and are 100x more effective than ordinary people.

have techs and building(s) supporting this.
2) add some variety to ships ie :
a) stealth, and revamp sensors to make them meaningfull.

support ships that can increase range, provide defenses, and other support to other ships
3) overhaul planetary defenses :
a) replace OFM, with a super OFM that also : (in stages by a new fork in tec tree)
1) extends planatary sensor range
2) provides off/def bonuses to ships in orbit
3) give a speed bonus to ships leaving orbit

make existing planetary defense system stronger, or just merge it into above.
Tac combat could be good, but i'm really afraid it's just something else that humans would be better at than an AI. Hence making the game easier, so that you'd have to play at masochistic or higher to get a good game. (personally believe AI's not cheating should be a the target difficulty level for someone pretty good at the game)