Just some ideas
I've also noticed some lag when launching somthing into space, And may i suggest Something?
(Here comes a broad spectrum of ideas @_@)
Ground based IP(Planetary)BM launcher, Like that satalite but can be used to defend against fleets as well as nuclear strikes?
Ground flight aircraft (not spacecraft of just normal aircraft to help defend from space attacks, Planet area only unless carried to another planet)
Space carrier, Can carry other craft to other areas, Such as space builders (Quickly) or Normal aircraft (Not spacecraft), this is meant to be a dropship for units otherwise unloadable by dropships.
Make a few uninhabited planets? (IF POSSIBLE)
Add a feature that could give use to ground units, so players just don't bum-rush you with a million fighters?
Add a fourth control point to each planet so when you ally with the other person on your planet that they dont screw you in population?
Add any other ground based mechanical units?
Tanks: Laser, Rocket, SAM (Added already, Good job on that one), Ballistic shell. Anything really, Its the future!
Artillery: Rocket-based (MLRS), Ballistic (Howitzer), Interplanetary (Orbital laser gun). Anything again. Your map, Your rules
Anti-air: this area is cruical, Since the main way right now to get to other planets is to go by spaceship. Which most defenses cant attack effectivly.
Flak (Area of Effect damage), Missile (Done already, and done well.), Autocannon (Add this as a kickass short range defence?)
Planet only aircraft Ideas: Fighter, Bomber, AWACS (Mobile radar).
Thats it for now. Good job and good luck.