from my games experience:

1/ first of all : review CAPITAL SHIP !!

these big fat slow ships need much more love aka more survivability
if someone is just focus fire your main while you decide to kill his little ship one by one : you should be able to micro it, and get some fun. Right now, your CAP is just destroy in a matter of second while your fleet got just the time to destoy 1-5 little bastard and reduce enemy powerfire by 1%
--> at the moment there is no tactical option : it is all about max power on your main cap enemy (except the first minuts...)


so CAP ship need
-to be faster than average ship
-have a better support (more powerful repair option?)



2/ second balance to be rewieved : RTS vs 4X
this game need much more 4X gameplay

for instance, victory should be also allowed with cultural/politics/economy
-it should have a sort of proposal of oath of allegiance for a planet : you not necessary need to conquer it with weapon. you get a tribut in return

-we should have also some kind of spy ship, which allow to get permanent info on ressource&planets opponent, but also prepare rebellion or generate natality disorder


we should have more diplomatic tools to manage ffa game : it need a panel which show player alliances statut with others