The AI is not invading on larger maps. It keeps its transport in or around the shipyard. It will be perpetually at was with a minor AI but rarely invades.
I signed up just to comment on this. It's absolutely insane that the AI is getting worse overall rather than better as these patches are coming out. I've only had the game since 1.5 but I remember several early games getting a barrage of fleets containing a transport moving towards my worlds, having to fend them off or lose colonies etc.
Of course some users rightly pointed out that the AI was crippling it's overall fleet strength vs logistics limit by putting a transport in fleets so should behave more like human players and attack with transports once worlds had been cleaned out. I don't think what people meant was the AI should just park them all in their homeworld or home shipyard and never use them again except for the occasional wiping out of a minor race.
In my second game since this update came out I'm playing a large map, 2 godlike AI and the rest incredible (I downgraded the rest in the hope that the two violent godlike AI - I picked Snathi and Drengin) would run over some rivals and take them out. To be fair to the AI, the Snathi crippled the puny neighbours they had and conquered one world... before simply waiting for it to culture flip back... the rest of the empire was there for the taking.
I rage quit the game finally when I wiped the Snathi out and took stock of the rest of the galaxy. The Drengin had built up formidable power (not compared to me by this stage as I'd taken a lot of good worlds from the Snathi...) compared to the Incredible AI nearby and in fact had wiped out every single ship on every single planet for their two neighbours they were at war with and conquered... 0... All I had to do was sail my transports over and into the worlds the Drengin had kindly cleared out for me...
I spent a bit of time over the weeks reading some of the AI discussions in the AI section and I must completely disagree with the assertion of the designers that 'anything the AI can't do too well that doesn't impact fleets/immediate gameplay' can just be fixed with bonuses and therefore ignored. That leads to some serious issues with 'fun'.
- The AI is rubbish at managing worlds. That's fine if they get huge bonuses and can just be 'fine' in early game anyway. BUT that really kills them by late game (compounded by them not adding any new worlds/growing their empires) so the game is fun early, then super ridiculously boring late game when the AI is just lost at sea. On top of that EVERY time you conquer a world from the AI it's such a ridiculous MESS you just think ugh this is going to take me 30 turns to fix. So I've got to the point where I figure well the AI never has more than my initial planets anyway since they don't conquer anyone so I can just ignore these new worlds, click 'research focus', click 'birthing subsidies' to get them as big as possible, replace a few tiles with farms and just ignore them. Yay research with no micromanagement... who cares since the AI is doing such a bad job anyway. Ideally you'd not inherit a complete mongol mess - you may as well just planetary bombard the hell out of planets since you don't inherit them in much better state after Information Warfare...
Don't get me wrong, I can't complain financially about the game since I got a lot of hours and fun out of it in 1.5 incarnation but having bought mercenaries, and seen the AI getting worse... like not invading me anymore worse... I'm starting to think this game won't ever live up to the amazing fun so many of us had with GC2... not without some major pieces of thought and work.
Oh and definitely fix the power graph thing. The AI gets a ridiculously inaccurate picture of your actual power from it. To the point of 'suicide declaring war' on you when it's far too late and it's totally crippled in 3 turns against your superior fleets. Also it behaves in the opposite way of 'sensible.' The Snathi and I are mortal enemies since the beginning and they hate me. I build a massive fleet on their border, with dozens of transports ready to wipe them out and my power graph overtakes them so they now 'love' me and focus on 'other things' instead of heading off this inevitable onslaught...