Try AOE tanking a heroic with Blue gear (I.E. the best you could ahve before heroics).
It stings. Alot.

And if you were smart as a bear, you would step back 3 steps, and hit swipe.
A pally howeever has a constant aoe planted on the ground where they are tanking, even if the ymove it's still beating the shit out of the CC'ed target.

IMO druids will be far superior for begining WOTLK, and pallies will become viable after badge gears starts proliferating across again.