This is part 2 of our look at PVPing with a spec mainly thought of by others as a PVE spec. Protection has waxed and waned in popularity as a PVP spec since Wrath of the Lich King launched. Its mobility, stun potential and kite resistance (as well as some nice spell interrupt utility), combined with excellent survival, weigh against its lack of raw burst potential. Protection can do many things well in PVP, from carrying a flag or protecting a tower or cap point to tanking in Alterac Valley or the Isle of Conquest, but its strengths are balanced by one factor. Compared to other warrior specs, protection in PVP just plain lacks the raw killing throughput of arms or fury.
This doesn't mean a prot warrior can't get off a Shield Slam that will make another player cross-eyed, because it can and does. But unlike arms, when prot charges a target and stuns it, even using Shockwave immediately afterwards, it simply isn't likely to burst out anything close to the raw damage of the non-tanking specs. If you're prot in PVP, you should be maximizing your strengths, not dwelling on your weaknesses.