I'll say that again. Warriors are not dominant in arenas. They are in fact under-represented. Blizzard would expect to see more of them in Arenas than there actually are playing. So the myth of the arms warrior owning all in his path in arenas is at least partially that, just a myth. Even in the one bracket (2x2 at 2200 rating) that warriors can be claimed to be overrepresented in, they still come in under rogues, warlocks and druids. There is not a single bracket wherein warriors are the most dominant class, not one single bracket at either rating.
So what's going on? If warriors are the most played class in the game, where are they? If you can't find one to tank, and they're not out there ruling PvP the way warlocks tell us they are (you'll notice warlocks are more highly represented in every single bracket at both 2200 and 1850 ratings, keep that in mind the next time a warlock calls for warriors to be nerfed due to their over-representation in arenas) then what's going on with warriors?
Is it possible that not all those level 70 warriors are doing anything at all? Have some of them, maybe a lot of them, been shelved? Is the warrior actually a class in decline?
Maybe, and maybe not. Let's discuss.
Partially this may be actually due to the fact that warriors are the most played class in the game. I've always had my suspicion that a lot of these warriors are alts, made by people who believe warriors to be EZ mode, and who don't really see a lot of play once it turns out that warriors are in fact pretty hard to play well compared to mana classes, who can stop and drink after a fight and be ready to go at full power unlike a warrior, who usually has to wait until at least a few seconds into a fight to be able to use any abilities. Tanking on a warrior is harder for some, because it requires patience from the group you're tanking for unlike a paladin who can start dumping consecrate as soon as the fight starts. Running a heroic with groups used to that kind of instant aggro is sheer torture, and it only gets worse if your warrior tank is actually well geared: the better a warriors' tanking gets, the harder tanking for five man groups who won't wait for aggro to be established is, because you simply won't have the rage to get anything done. I've taken to tanking heroics in my DPS gear just go hope to get enough rage to hold aggro with people throwing wrath, fireball and so on before I've even gotten a chance to use a single devastate. And to be honest, that's in groups with good players that I know.
I won't run PuG's. There's no reason to. First off, most PuG groups have no idea what it takes to hold aggro on more than one mob and won't let a warrior do his or her job. Holding back for a few seconds seems to be like stabbing yourself in the hand with a red hot butcher knife based on some of the PuG groups I've run with, if each DPSer isn't immediately hitting a different mob within two seconds of a pull, something's wrong with the world. In order to get a pick up group that has good players in it that are willing to do what is necessary for a warrior tank to hold aggro, you have to beat it into their heads. Frankly, I don't like yelling at my groups. That's why I like raiding so much more: if someone does something stupid to pull aggro off of me or breaks CC, then the raid leader will yell at them, leaving me blissfully unburdened with the responsibility of being aggro mommy.
Secondly, there are apparently a lot of really bad warriors out there. I mean, not just DPS warriors who can't watch their aggro, but a lot of warriors who show up to tank Shadow Labyrinth in 'of the beast' gear and a level 63 green sword with 2.6 speed and who don't know where the Shield Block key is on their keyboard. And so, a lot of DPS are trained to believe that all warriors are mouth breathing, drooling idiots who couldn't hold aggro if they had dirty pictures of Hellmaw's mother taped to their foreheads and it's best to just nuke wildly since you're going to die anyway.
This may sound harsh. You may be thinking "I've run hundreds of PuGs and I never do any of that." And you probably are entirely right. But for every player who knows how to target the skull and not hit the square, there's players who break sheeps early, keep DPSing square even through it's the secondary tank target and then wonder why it ran over to hit them in the face (usually with a "Hey tank, learn to hold aggro" comment afterward) or what have you. This means that for most five mans and heroics, AoE tanking is just the only possible option. It doesn't require complicated CC at all. I honestly won't run a five man anymore, I try and make the guild paladins do it. Sure, I could tank Shattered Halls. Hell, with my gear, I could probably tank it in my sleep. But a paladin could tank it faster and without having to set marks or explain kill order. Paladin tanking for these instances requires a lot more work from the healer, of course, probably more healing than you'd need if you brought two warriors for an offtank, but at least it's single target healing.
As for Arenas and PvP... well, quite frankly, unless you're geared ridiculously well, warriors are in fact not the murder gods of PvP, destroying battlegrounds with ease and crushing all faces that stand in their path. Undergeared warriors (that is to say, most of them) in PvP are easy caster fodder, and don't really do much better against melee. They get stunlocked, rooted, frozen in place, Death Coiled and then dead. Dead to dots, dead to poisons, dead to raw damage. Casually kited around, and stunned if they try and use intercept to close the gap. The life of a warrior in PvP is to be easily, casually crushed over and over and over again until you finally have decent enough gear to be able to come back and say "Remember me" to those that used to kill you with the kind of contempt you or I might swat a mosquito with. And when you finally get that gear, and can put up a fight?
Well, you can see what happens. People complain about warrior 'dominance' because a warrior managed to kill them once. Even though the warrior had full season 3 and a Vengeful Gladiator's Bonegrinder, and the caster in question had a few pieces of season 1 gear and still managed to burn off half of the warrior's life, it's somehow unfair that the warrior killed him. The very idea that a warrior might manage to close the gap long enough to actually hit a caster seems almost viscerally horrifying to the same people who think nothing of standing at a distance and killing one before he can even get a hit off.
I love playing a warrior. I love tanking. I even love getting on the tauren and running a few BG's or spending the day in a few arena matches. But I do these things with the full knowledge that other players don't understand them from the perspective of a warrior. There are those that do, yes, and I love those people. I'll tank even the most ridiculously conceived bad PuG consisting of three ret pallies and a moonkin healer if one of them is my friend in game, even if I know in my bones it's not going to go well. But I don't blame other warriors for not wanting to deal with it. A lot of warriors get into guilds and never run a PuG again, and only PvP with a couple of friends when they have a day off to respec for it. And there are a lot of warrior alts out there gathering dust while their players revel in the freedom another class offers. As much as I love my warrior, who has a very nice collection of epic tanking and epic DPS gear, I hate farming on him. I'll sooner get on my enhancement shaman to do it, he farms at about five times the speed due to his greater... much, much greater... damage output. And I'm simply not willing to eat the respec costs to gain actual DPS for an afternoon only to go back to tanking that night, it's just not feasible to spend 100g for a day's farming. I mainly do dailies on him to get prep money for the night's raids and then log him off.
Long term, in it for the duration tanks and DPS warriors and PvPers, we're not going anywhere. But we're not everywhere. The reason you can't find one is because there's less of us than you think, and those of us that are here, we're already out there doing the stuff you want from us for someone else.