I didn't know you could quicksave (ctrl+s) on the campaign map, that helps a lot, and I've also noticed that if you do ctrl+s, hitting esc after doesn't CTD, at least so far. Weird.

As far as stuck units goes, merging other units into them doesn't free them for me, and I don't like using the auto-merge feature. Generally now I don't ransom back units unless they are particularly high-value ones, if I do and they get stuck, I just wait for the next restart, when they will be unstuck.

I've never had it happen to bribed armies though.

Despite the above, all in all I consider myself lucky not to have anything more severe, considering some of the problems I've read about.