A lot of people seem somewhat terrified of the new Vengeance mechanic and how it might play in PvP. People are always leery of tanking specs in PvP, due to the general tendency of people playing in arenas and BGs to want to, you know, kill the other guys. Tanks are generally designed to be harder to kill, which tends to make people nervous, especially when tanking specs saw increased damage output in Wrath of the Lich King and went from "Hey, guys, look, it's a free kill!" to "Wait, you mean trying to burn down the dude specced and geared to not die is a bad idea?"
The forums seem to be rampant with terror that Vengeance will rule them all. I personally don't see the concern. Vengeance doesn't stack up terribly fast and it falls off fairly quickly; you'd need to focus fire a tank for significant levels of damage while he was being focus healed (and you'd need to completely ignore his or her healers) in order for Vengeance to really be a concern.
But don't take my word for it -- just ask Ghostcrawler. Not only do the developers not think Vengeance will be an issue in PvP, if it turns out to be, they'll just turn it off.
I don't think Vengeance will be an issue (I actually had to chain pull close to 20 mobs in Uldum to get the level of Vengeance-stacking that's being discussed here) because in order to get it so high that it provides this kind of benefit, you basically have to do between twice and three times a tank spec's health. If you actually beat on a tank for that much damage and he or she isn't dead, you have a better target you should be hitting instead: the person or people who is making that tank not die.
Still, if I turn out to be wrong, it's good that there's an easy toggle to prevent it from being an issue. I'm not thrilled with the general consensus that tanks should be walking meat bombs ripe for the DPS players to murder, but at least GC holds out hope that tanking specs will have things to do in rated BGs.
I would admit to being biased here, but frankly, I hate PvPing as prot. Still, if someone wants to do it, I'd like it to be somewhere between the admittedly berserk highs it got to at points in Wrath and the absolute joke it was in the previous expansion and original game.
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