Apologies if the conversation is, like, mad old (couple of weeks Internet Time is like a decade of Dog Years, mirite?), but I'm thinking about the Boundaries idea, and... uh... are you asking for movement through / setting up shop in someone else's area of influence being restricted by the game engine? Basically, enforced by The Hand of God the way the United Planets laws are currently setup?
That would be obnoxious and incredibly artificial, IMHO. Much like the current UP law system, except on a much larger scale. I can live with the current UP laws because on the whole they tend to be pretty small fry (Can't blow up a Freighter? Who's stopping me? Oh: God. Well, alright, there are more important things I could be doing, anyway).
On the other hand, if you're asking for the AI to react more intelligently to my moving through / setting up bases inside someone else's AOI, then I agree wholeheartedly. Yes, if I fly a fleet of enormous warships through the airspace (spacespace?) around your capital planet, please do get mad at me. Let's see some outrage.
But then what you're really asking for is a more Diplomatically savvy AI. Not "boundaries."
Basically, I object to the idea that I would not be allowed to fly my Incredible Fleet of Monster Warships around wherever I choose, using their Gigantic Guns as a self-issued passport. If you can blow me out of the sky, then feel free to tell me to GTFO. But if you can't, then by all means shake your fist some more while I airdrop the accumulated sewage waste of a billion footsoldiers on your "Empire's" version of Washington D.C. en route to wherever I damn well please. My Guns Give Me Clearance.
The Diplomacy system should be the next major upgrade to this game. Don't make any ship attack equate to a war declaration - that's step one. If the AI sends ships inside my AOI I should be able to request that it turn around and retrace it's steps until such time as the space it is flying through is not me-colored. If it refuses, I should be allowed to mail it back home in installments. If, upon receipt, the AI decides to declare war on me, that's ok, too. If that's not a war the AI can fight, it should get really mad and look for other ways to achieve satisfaction - calling on allies, appealing to the UP, paying off pirates to exploit my border worlds, etc...
Also, UN laws should be breakable and result in inter"national" incidents.
Yeah, I realize this is an incredible amount of work to add to the AI, but IMHO it's really the only acceptable solution to the "wut iz dat starbase blaring infomercialz at me well ok i guess" weirdness of GC2.