Given that previous lore indicated that without constant Domain supplies terraforming is a Big Thing to the point where the sector collapsed for lack of it, a terraforming item/module should be something that'll attract A: jealousy, B: offers for it (Chicomoztoc but habitable like Gilead? Hegemony want), and C: should be pretty amazingly resource intensive to deploy. Seriously amazingly expensive. Gratuitously expensive. Victory lap expensive. Otherwise, who wouldn't have been terraforming?
As far as rarity for forges and synchrotrons, it was really cool to find a corrupted nanoforge for the first time. And a synchrotron. However, corrupted nanoforges are all but worthless after the exploration phase and you don't really need more than one or two synchrotrons while you'll easily find seven or eight of the things. Pristine nanforges are still valuable-ish from both their rarity and boost to construction capacity, but by end game the player will be able to just spam out orbital yards with corrupt nanoforges everywhere, only need one pristine nanoforge for the quality boost, and that's good enough. You won't replace millions in a month such like if everything was pristine, but really who cares it's surplus to all but the most ludicrous of needs.
I'm honestly not sure what to do with AI cores. The alphas are without exception useful one way or another (Better administration without impacting cap? Better Access? Bigger fleets? More ground defense? Okay, sure, I've always got a use for that somewhere or other) and I'll drop them in somewhere, but it's rare that the beta and gamma cores are useful now. The beta core maintenence reduction is effectively useless with a comprehensive industry list, and that just makes them gamma cores. You might consider making beta cores change how industry responds from shortages from losing a trade fleet or something, I dunno. They need something more.
On a funnier note, while I was trundling around with frigates in my new game I noticed a small pirate raiding group fleeing from pursuing Hegemony forces that had the radar signature of an armada. Turns out it was an armada originally, but the minimap signature didn't update after it got blasted to pieces.