To me, the oppressive atmosphere is still there, in Diablo 3. The world was changed when the earth stone was destroyed, and it's been a while since then as well, so of course there's changes, but it still has the things that made Diablo 2 great (at least to me it does). Killer monsters, killer loot, good but not overpowering storyline, an amazing look to the design of everything, and amazing blizzard art. The one and only thing I'm a little disappointed by is the lack of the assassin class, cause I LOVE dropping traps, and killing huge numbers of baddies. That was my favorite class to play. But that's it. I'm loving the art direction, and everything else I've seen so far.
On the cinematics complaints, they don't really hold water. The "class" cinematics are just introducing you to the class, that's it. They're not supposed to be full-fledged, high res cinematics, like the announcement cinematic. It'd be bad ass if Blizzard made high res intro cinematics for each class, I'd absolutely love that, but those take a LOT of time, and effort, and money, so I'm not surprised they left it to in game assets. The REAL (for lack of a better word) cinematics will be in the game like they always are, to push the story forward.
Well, that's my thoughts anyway, and I'm no WoW fan, or blizzard apologist. I just don't see how people can complain about Diablo 3. The second one was over ten years ago, of course thing's are gonna be a bit different now