The PC version certainly has auto attack. If there are any bugs in it, it happens with various spacing and pathing issues. Attacking someone who's running away from you is as glitchy as I've seen it to this point. It still works even then, just a little slower than usual. It's certainly not a game breaker. I can't comment on the console versions as I haven't played either.
I just finished my first play through, which I usually do on normal mode so I can whiz past everything and experience the story like a long movie. It was mostly quite easy on normal mode, which is what I'd expect, but I got some surprisingly more difficult fights mixed in, like the one against
! the high dragon. (not much of a spoiler, I know)
Overall, I really enjoyed it, and it took longer to beat than I thought it would after the Awakening mess. The writing is good, and I got a lot more connection to the Origins/Awakening story decisions than I expected. A lot more. I can remember off the top of my head multiple quests which were only available because of my decisions in Origins. For example:
! I had to help a member of the Harrowmont family who was being hunted down by King Bhelan.
I was worried about a huge tactical regression in this game before it was released. Other than some balance issues, though (like the crushing prison nerf), the only real tactical differences are the lack of an overhead view and the removal of friendly fire. Mages can now go apeshit without worrying about killing the pesky rogue in the process. They said they took out the overhead view for design reasons. I was worried when I first heard that, but in the end it doesn't appear to bother me that much.
I'm making some assumptions that nightmare is quite difficult, especially in the harder fights. Unless that assumption winds up being wrong, and I won't even know for a month probably, I'm quite happy with this game. Bioware may have ripped me off with Awakening, but I feel my money was well spent this time. Hell, even if nightmare isn't very difficult, the game will still provide me with a good, solid month of fun, at least.
One complaint I do have is that this game has less freedom with stats than Origins did. The top weapons require 41-42 of the main stat, and each class has a secondary stat they need to worry about as well. After putting 40 into one stat and 30 into another, there are very few additional points left to play with at all. In Origins I could make a cunning rogue. In DA2 it's quite challenging to make a rogue who can even match their dex with cunning. I was very close to that near the end.
Edit:
Oh yeah, and for the record…
! Anders was way cooler in Awakening. They ruined him.