Cataclysm zones aren't too bad for leveling boxed.
The druids did every quest in Hyjal, Vashj'ir, Deep, and Uldum.
The DK's/Pally skipped a chunk of Vashj'ir and did some of Twilight Highlands.
My knock on Cataclysm is how linear it is.
You cannot go to hub B, until quest hub A sends you there.
Aside from that, the level pace is fast and the collections (which you cannot really avoid) aren't too terrible.
You can basically choose one of the zones to skip, and do most/all of the others.
You're best off (from the point of view of leveling speed) to immediately move to the next zone as soon as you qualify: Deepholm (at 82nd), Uldum (at 83rd), Twilight Highlands (at 84th).
Some of the quests benefit greatly from a macro.
/Target Whatevertheannoyingsquirreliscalled
And then IWT.
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