Looks interesting, not enough to tempt me back atm (RL), but cool none the less.
Lich King was on a different continent, when I left it the Argent crusade were building an arena and asking horde / alliance to leave their differences behind to joust on giant chickens.
I can see why they've done it, the 'old world' looked positively dull compared to the new, and the thought of levelling up alts through the old content again was fairly galling, if not achronistic: they've effectively given the whole series a reboot.
I'd imagine the newbie zones are fun, and tied into the new characters / classes. With the 'cataclysm' they'll wipe the slate clean. (that said some forums seem to think the whole area will be 'phased', personally, I hope not. it would make matters ridiculous).
It will still be WOW though, grind, loot, ding! rpt.
NB - It is of course the 5th aniversary of WOW - cue
http://www.worldofwarcraft.com/info/und ... xia20.html