I'm still pretty positive about WoTLK after having played on and off for another month. I seem to be about the slackest person I know since Megeara is still only level 73. I'm basically a Bartle-type explorer, and there's been lots of fun stuff to see.
In particular I've enjoyed being a forsaken alchemist, since Northrend seems to be filled with evil alchemists spreading the plague over the hapless inhabitants. There are purple-hued enclaves clouded with drifting poisons, and cackling forsaken hacking up bodies to create hideous undead monstrosities. It speaks to something deep in my undead soul.