I think military starbases might be a little overpowered. My ususal starategy is to get medium ships with 1 armor, 1 engines and the rest weapons. Next I build a military starbase and equip it with +3 defense assist module, I just match up whatever wepons the comps are reasearching, they basically all get the same weapons. The defensive bonus practically makes my ships invincible. I can can wipe out any computer fleet without losing a ship from mine. When invading planets I just build a forward military starbase.I can easily win conquest victory on painful setting using this strategy. My last game I killed 180 enemy ships and lost only 10.