Finally done leveling with the paladin last night. Hyjal 80-82, maybe 2/3rd of Vashj'ir to 83, Deepholm to 84, and Uldum to 84.9. After the few prep quests for Twilight Highland at Stormwind and about five quests in the TH zone, I dinged.
Without experiencing TH, Hyjal and Uldum are my two best zones. Vashj'ir is the one I anticipated the most but it bored me out of my mind I couldn't even finish the zone. The underwater aspect is cool at first but it got old in about half an hour and then it just felt gimmicky and annoying.
Hyjal has a great storyline and takes the cake for the most epic finale quest ever. I'd guess that this feeling is especially true to people who raided Molten Core back in vanilla. The nostalgia effect is in full speed here. Did anyone else say 'LOOT THE DOG!' out loud the first time you saw an area full of core hounds and lava surges?
Uldum is just simply excellent storytelling and the way the quests are setup with cut scenes every other quest like we're playing a movie is just amazing. I can imagine how some people are annoyed with this though, and maybe I will be too on the next 2-3 run through. Heh.
I'd rate this expansion 9/10 for Blizzard, purely for the questing experience from 80-85 and leveling a new character in the undead area from 1 to 35 (not having touched any new dungeons or raid instances).