Does the AI ever surrender to anyone other than the race making war on them? I constantly have hopeless case minors and majors pleading for help but I can't seem to flip them even with culture palaces, huge influence and strong military. I get plenty of random culture flips but it seems only force or the threat of force will induce the release of a star system on the diplomacy screen.
I read somewhere in a thread that all the minors except one (Alexians?) are immune to flipping.
There's a button on the interface (I played like 5 games before I knew it was there) that lets you know the exact influence in a sector. That's useful for causing flips.
So far on Intelligent it seems the AI isn't quick enough in stopping culture attacks -- I was in danger of losing a system, so I crank out the constructors... next thing I know AI is demanding one of the starbases... but the remaining ones 'cause their system to flip to me.
The downside is this game is too much constructor management as it is... I avoid the starbase-culture route normally.
I know for a fact that the I-League is not immune to culture flipping, and I'm pretty sure that I've seen other non-Alexians culture-flip. I'm pretty sure that they don't culture-flip as easily as the majors do, however.
Could be that has something to do with it being harder to culture flip the last remaining system of a race. Since most minor races will only have one system in most games that would make them hard to flip compared to system 19 of the Torians or whatever.
Or maybe home systems are immune to culture flips...
I don't have any facts to base this on, but it would seem likely that the developers would have made it harder to completely wipe out a race by culture flip.
I've had the Alexians flip on me, including their last planet. But then another game I sold a really crappy class-15 planet to the Drengin, in a sector where I had 3 fully-developed star systems. It flipped even before the lease was over. Then I repeated and sold that same planet to the Altarians. Again, it flipped within 4 turns. Then I sold it to a minor race (not the Alexians...Carcinos? the one that starts with a C...). Their morale fell below 25, but it never failed a single saving throw. This is 1.0.3.