I think you missed my point.
Here we go, right now Prot is scaling almost entirely with AP and for the most part so are Arms and Fury now. They've done this change so that we scale less with our gear (especially weapons). Because of this and especially the addition of Vengance which is pretty much straight up doubling the AP of Prot the Prot spec is rather beastly, this is especially true leveling up where you'll get the most out of the additional survivability and with the increase in critter damage it should be even more important while world-questing.
So as Devlin said Prot spec in DPS gear is going like a steam-train and with shield spec it probably has some of the best rage income in the game and as we all know more resources = more damage.
However as we gain mastery Arms and Fury should be able to pull ahead of Prot as far as DPS is concerned depending on the coefficients and how well it works. Like if Arms can get up to a 50% chance of extra swing pretty quickly then that'll manage to put the damage way ahead of the extra AP Prot gets through vengeance. Same with Fury if they can buff their enrage to 25% or greater additional damage and get it up closer to 100% of the time then they should pull ahead of Prot.
So hopefully by the time we start raiding Prot in any gear type will be at a slight DPS disadvantage compared to Arms and Fury.