I was leveling ret but recently swapped to prot to try it out and I have to say that this is ridiculous. In Cata I'll see no point in leveling outside the instances. my only complaint is that the satchels tend to give you crap loads of variations on items. I honestly had 5 plate shoulders at level 36. I'm also leveling with the BoA chest piece, but I honestly won't be spending more emblems at the rate I'm going.
And just FYI I'm getting an average of ~3 seconds on good days and ~26 seconds on the odd day.
Do you think blizz will do something to stop us from just running instances to level come cata?