personally I don't find 1.5 really buggy having played it since the opt-in
I haven't noticed massive problems, but there's clearly problems with Beastlord, and the "two units on same tile" problem is new as well. I've also noticed some diplomacy weirdness which I'll write up tonight if I have a chance. There wasn't a massively long beta for 1.5, I assume because there were such big problems with games hanging in 1.4. I've put in a request that we concentrate on stability in the next patch.