So I randomly decided earlier today to try and spec my (level 65 in greens) Warrior to Prot just to test it out with the beta changes. All I can say is- amazing! It's not the fastest killing thing in the world, but it's so very interactive and I really enjoy it quite a bit. I feel like I'm back in Vanguard playing my Monk with all of the reactive abilities and cooldowns and whatnot. The new Shockwave talent combined with Concussive Blow and the improved Revenge talent give you a lot of stuns. Sword & Board procs are a lot of fun as well, adding further to the reactive element.
In a way it's a lot like Affliction in PvE- kills slowly but has some survivability as well. It's refreshing after getting mowed over on the premade server on a Warlock. (Warlocks are all kinds of squishy on the beta)
Anyway, I would go so far as to state that I enjoy Prot more than I do my Deathknight. Deathknights kill in PvE way too quickly (although Leiah has been saying they're pretty low DPS in the arena) Even specced Unholy the burst is pretty high, though no more than any other standard DPS class, which I really don't enjoy. I suppose I enjoy the thrill of combat more than I do the thrill of the kill- which is why I never really cared all that much for Rogues/Mages/Destruction etc.
If you have a Warrior make sure to copy em over to the PTR server and give prot a spin!