troop upgrades again

[TKF]

since there are armor upgrades requirements for tanks, players do only upgrade armor for the same reason. Also structures are harder to kill, while non-combat buildings have no gain for attack upgrades. But also attack upgrades do improve orbital control, mines and bomb.

Also armor upgrades make creeps harder to kill, weapons upgrades does only apply to their attack power, which doesn't matter when they don't hit you.

I can agree that armor upgrades in general are bit stronger than attack upgrades.