In the last three games GalCiv2: DA b2 games I've played I had great relations with about 1/2 of the empires, and so so with about 1/4 and there has been just one that really had it out for me.
First game I was a custom, then the Thalians, then the Iconians; and about mid game, somewhere around the first empire getting knocked out it happens, like clockwork...
One empire attacks me, and within 20 turns, all the rest of the empires attack me! It seems not to matter what alignment I have, what my relations with them were, or the size of my military. In fact, in the last game the three *strongest* empires were all friendly/close with me but after only about 10 turns declared war.
This has killed the fun of DA for me. It's impossible to keep ALL the empires liking you. I don't usually complain about game dynamics like this, but I have been telling people to buy GalCiv2. If this isn't fixed soon, I'm going to recommend they leave the expansion on the shelf and pick up SC.