Mage burst and feral burst comes around quicker than either of these 2 classes, sure it isn't for long, but it is more frequent.
Warriors were OP in 5.0, which everyone said during beta they would be, but Blizz would not listen. Instead everything went live, people went "OMG OP CLASS!!! MUST REROLL TO FOTM!!!", there then became many warriors. Warriors get nerfed, class isn't broken, there is no replacement FOTM, so those people stick with it - that is why you still see so many warriors around. Come 5.2 with the monk and rogue buffs, and additional nerfs to warrior (survivability and control nerfs), there should be a shift in numbers. Mid season people dont like to reroll unless a class is truly broken, and to ask for MOAR NERFS is blindly following the pack simply because you don't know how to avoid it.
Warriors have never had actual control or survivability before MoP, and at the start they were given too much - gag order, shockwave, double charge / warbringer, defensive stance not restricting damage and giving 25% damage reduction and ofc second wind.
Lets put this in perspective:
Gag order - Removed.
Shockwave - doubled CD as of 5.2
Warbringer charge - Added to DR table, despite being a 3s stun, as opposed to many classes 4-5s stuns.
defensive stance - 15% damage reduction as of 5.2 (coupled with overpower now having a rage cost restricts damage somewhat)
second wind - a warriors Only heal, assuming they are not getting killing blows, and it also only takes them to 35% hp, which is just above execute range for some classes.
Warriors did lose things they had before to gain some of these abilities - their root / aoe slow, must now choose between them for talent.
Throwdown - an arms warriors previous stun of choice, and it was possible to get this and gag order back in cata, people dealed with that then.
Blood craze / Old Second wind / Enraged regen - 3 healing abilities, now cut back into 1 talent choice. Blood craze would proc 1/2/3% healing on damage taken, second wind would recover health and generate rage whenever stunned/rooted, enraged regen was a baseline ability, now a weak talent choice - 60 rage cost to use without being enraged. It's a 10% heal with a 2%/s for 5s hot added on top, would be nicer for the % heal to be based on amount of rage - 100 rage = all up front heal, but that's for another topic.
Warriors are going to defend their position because of the suffering of the end of cata - especially when compared to rogues. Mages have always been strong, and feral druids also. To have any one of those classes (especially) asking for warrior nerfs is just going to bait defense and calls of QQ.