Yeah, other than beefing up their health a little bit, I don't really see any reason to tinker majorly with golems. Like others have said, there's already an extra cost associated with them, in the form of increased waves to the planet in question, in addition to the several hundred thousand energy units and ungodly amount of metal/crystal required to repair them. Now, some might think "oh, it's all metal/crystal", keep in mind that you're probably using that metal/crystal to build fleet ships, starships or defenses. If you've got enough surplus that you can just say "ok, let's activate this golem" without even blinking, then you're probably playing at too low a difficulty level anyway.
My one experience with golems so far was kind of unfortunate, I captured a planet with a cursed golem, then got hit elsewhere with some size-2000 AI waves, at which point I forgot about the golem - until I went back to check that planet about half an hour later, and noticed the golem was gone. So I guess I should have set an alert on that system, but it also had two fabricators, and it was pretty much impossible to defend all of them at the same time.