So far I am really enjoying Cataclysm though I've only been questing in Hyjal with my UD mage (now 82) on DMF.
And fiddled around a bit with some alts. I had no plans at all of making a goblin other then to see the starter area but I have fallen for my cute little girl so she will continue to explore the new world.
Leveling seems a bit too fast though, got from 80 to 82 in two evenings playtime and I took my time reading quest logs and enjoying the scenery.
Oh and I loved the quest in Hillsbrad that I did on my lvl22 priest where I had to appear as a questgiver to 3 different npc's, I havent laughed this hard in a long time.