I always liked the lonely abandoned feel of Azshara, even if in game terms it was kind of a useless zone. So i'm a bit sad it'll be over-run with goblins.
Anyway though looks like they really are redoing the entire world. Some places will be all churned up but from that trailer I'm sure I saw Desolace transformed into something green and bountiful.
No mention of Emerald Dream, maybe they're saving that for another time.
Not hugely interested in the new races personally. Werewolves as a concept bore me, I guess i could go with a goblin.
Of all the new options what I'm most keen to try out is a Troll druid. Expanding the class choices represents changes in the world as races learn to adapt. I mean Taurens are spiritual guys so them being Paladins and Priests is sensible. Dwarf Shamans has precedent in lore (the wildhammers). Night Elf mages are harder to swallow but, eh, desperate times desperate measures etc.
Stats to be simplified, which works for me. I never liked puzzling over whether I wanted more agility or attack power on an item.
Does anyone know if Northrend will get, er, Cataclysmed? Will anything there change at all? I'm wondering how this all works in story terms; obviously we as players are doing all the parts of WoW all at the same time. But I thought expansions were meant to represent events in the world, ie Lich King actually "happens" after burning crusade and these are both a year or two in the future for a level 1 character.