This is interesting. I find it kind of frustrating when Bornakk posts on tanking issues, because I just don't get the impression that he understands what he's talking about. This may be an incorrect impression and in fact he could be the world's foremost tanking expert, I just don't know.
Let's run with Bornakk's comment about wipes with the boss on 500,000 health. The current feeling seems to be that there's at least 500 dps difference between a warrior tank and a similarly geared tank of another class in a raid boss situation. That in any event is the sort of number I see regularly (I raid with a very skilled but slightly grumpy paladin).
On the assumption therefore that a fight lasts say 7 minutes, that translates to me doing 210,000 damage less than my fellow tank in that time. By Bornakk's logic therefore, every 7 minute wipe which occurs with the boss's health at less than 210,000 (I have been involved in two such wipes in my last four raids) is a direct result of my dps being underpowered compared to other tanking classes, and would have been avoided if I'd been switched out for a paladin, druid or death knight. Low dps definitely does increase raid wipes - to say otherwise is at best disingenuous.
I find it really bizarre that this has not been addressed. Blizzard must surely have their own tools to monitor dps, and there is a massive disparity between prot warrior dps and the dps of other tanks (being offtank in VoA25 where the DK main tank was doing 4k on Koralon while I pulled 1.7k was pretty upsetting). I really don't think that the answer is for me to L2P - my rotations are pretty good (although the prot warrior rotation is very challenging) - it's just that warriors are underpowered. Saying "you are underpowered but it doesn't matter" is pretty pathetic really. You might as well say it's ok that warlocks are underpowered but that's ok because rogues and mages are overpowered so on average raid damage will balance out.
I also can't believe it's that hard to increase PvE prot warrior dps without breaking PvP. Here are some ideas which took me 5 minutes to put together:
1) Make rend useable in defensive stance
2) Make thunderclap apply a dot (referred to amusingly as "the clap" on the forums)
3) Reduce the base damage of shield slam/revenge, but make it so that shield slam/revenge damage increases with the number of sunders on the target, so that damage when there are 5 sunders up is higher than now.
4) Reduce the damage of concussion blow to something sufficiently low that it's no longer in our single target dps rotation (this will simplify our rotation and balance the rend thing).
5) Make one of the deep prot talents increase the rage cost of heroic strike and the bonus damage. Alternatively you could do this via a glyph.
EDIT - Looks like someone at tankspot had the same idea as me, and damn well made a graph about it. The difference in dps is apparently 1k on average, so that would be nearly half a million damage in a 7 minute fight /boggle
Still don't reckon the disparity is a big deal? I'll start polishing my fury gear...