One thought I had is some sort of penalty for multiple golems, maybe bring back the per planet damage penalty for multiple golems on the same planet?
Not a huge one mind you, activating multiple golems should still be advantageous.
My reasoning for this is because the golems are powerful super weapons, 2 golems together is significantly better then 2 golems working solo, 3 golems together is getting into the stupid-powerful range and 4 golems is insta-death to anything else.
That way individual golems can stay as the powerful superweapons they are, while stacking multiple golems could be balanced better so they don't become more overwhelming then they are intended to be.
(Note that I don't actually play with golems on much, I'm extrapolating from what I've seen in other powerful units quite a bit here.)
D.