I have the live stream (Hey, I take what I can get here in Australia!) and have to say, I've been thrilled with it all.
I'm a die-hard hunter since Vanilla, and this is the first expansion that's actually made me look forward to it with eagerness. BC I completely skipped (Burned out over-raiding aq40 and naxx. >.>) and Wrath was good but nothing really 'grabbed' me.
I'll probably reroll a worgen hunter, at the least. I've always loved the worgen, and am really looking forward to playing them. =)
I think that revamping the old world is definately the way to go and much less cheesy than a 'forgotten' continent or a risen one or whatever. I think WoW has come a long way in the last 5 years, and the chance to streamline the whole experience with what's been learned from the quest flows of BC and Wrath are only going to do good things for the playerbase. Leveling alts will be much less chorelike and much less 'run around everywhere!'.
I love that Ragnaros is back, and looking for revenge for that whole MC thing. =)
Goblins are a bit meh to me, but then, I've never really played horde, so I'm not fussed. I suppose if Worgen had gone Horde, I'd play them still, but I'm glad they didn't.
All in all, I'm hooked! And they didn't, y'know, redo it like this and release it as 'World of Warcraft 2', and try to maintain both in parallel, like some other game I could think of.
Not to say they aren't remembering EQ: I am pretty sure EQ had an expansion focusing on the elemental planes, and implementing a system of small character perks/improvements not connected with levelling. One could, perhaps, call it an 'alternate advancement' system.
And this looks like it's going to be every bit as controversial as PoP was in EQ, with a loud subset of the population yelling 'No! You're making it too easy! I ground uphill both ways in snow, so noone should ever have a shovel!', while most of the population is quietly going 'Wow, this sounds less annoying and more fun!'.