I really want to like haste. I really really do. The problem is, it just doesn't do as much for us as it would have to for me to like it. What would it have to do? Well, for starters it would have to reduce the cooldown on our rage generation abilities. The fact that no amount of haste affects, as an example, my Mortal Strike or Bloodthirst or Shield Slam cooldown hurts the stat for us. I've tested this by stripping completely naked to ensure I had no haste at all, then putting all of my gear back on and having 6% haste - 2,545 haste rating - and making sure that none of my abilities can be used more often. While haste still does increase our rage generation in Battle or Berserker Stance, by increase how fast our autoattacks are, this is a piddlingly low benefit compared to other plate DPS.
It does even less for us as tanks. Some tanks like paladins and DK's are able to use haste items as tanking gear, because the haste increased their resource generation and thus their active mitigation. But for us, haste does nothing for tanking because we generate no rage from autoattacks when we're in Defensive Stance. There are three plate classes, all three can tank or DPS, and of those three only one of them gets minimal rewards from haste as melee DPS and absolutely nothing from it as a tank.
Now, we've all heard the argument that it's good for each class to be distinctive and like different values on gear, because it means they don't play like carbon copies of each other, and I'm willing to acquiesce to that argument. Furthermore, this isn't a call for buffs. I'm not lamenting warrior tanking or DPS right now. This is more from the perspective of design elegance and scaling, because it's not like gear with haste on it is going to go away and we can't just excuse everything with the just reforge it mantra.
Go faster, tanks
Making haste desirable for tanking warriors means either allowing it to increase rage generation for them, allowing it to reduce the cooldown on abilities and/or the global cooldown for them, or potentially both. The easiest possible solution here would be to allow warriors in defensive stance to generate rage from damage dealt, but that runs the risk of making Defensive Stance too attractive for PvP and DPS uses. However, haste could also be used to increase the passive rage generation of D Stance - simply allow haste to reduce the interval between rage ticks. At present, Defensive Stance grants 1 rage every 3 seconds. Haste could reduce that time, so at certain break points you were generating 1 rage every 2 seconds, or even 1 rage a second. Tuning haste to be worthwhile without being absurd would be a challenge, but not only would it make haste a reasonable stat that you could make use of (meaning that when a haste/mastery or haste/expertise piece drops tanks don't have to sign and shake their heads at it) but it would also make a Bloodthirst/Heroism/Time Warp do something for warrior tanks like it does for every other class in the game.
The Speed of Death
Now, for DPS warriors, haste isn't as clear cut. For arms warriors, haste is debated alongside mastery once we get our hit and expertise close to cap. No one's debating crit, of course - as long as our enrages are directly reliant on a critical hit Mortal Strike, Bloodthirst or Colossus Smash, we're going to stack critical strike like demented aliens from planet Jenga. For fury warriors, I'd argue that mastery wins handily due to Unshackled Fury. Since we're stacking crit to enter enrages, mastery then makes those enrages better, a synergy that maste simply cannot even come close to matching and the reason haste remains a dump stat. But we still have to admit that for DPS warriors in either Battle or Berserker Stance, haste provides some benefit because it makes our white attacks faster, and as a result increases our rage generation.
Now, it's reasonable to argue that we have to have some stat we can ignore. We already have hit and expertise to soft cap, crit to stack like a crazy person and then mastery as a fallback stat. Allowing haste to be our dump stat would be fine, except that we're the only plate DPS that feels that way about haste. With ret paladins and both DK specs liking haste more than we do, we end up with gear that's either itemized well for us and badly for them, or gear that's perfect for them that makes us go 'huh' and consult our favorite reforging site or addon. I recently downgraded from a hit/haste heroic DPS neck to a normal mode drop that had crit and hit on it and saw a DPS increase. (Admittedly a small one.)
Honestly, the only real improvements I can see to haste for DPS warriors would be to either allow it to reduce our GCD, or allow it to reduce the cooldown on our rage generation strikes. Either option would require very careful balancing and it's not likely to happen while warrior DPS is holding steady in the center of the pack. Until it is addressed, however, haste will continue to be slowing our DPS down, not speeding it up.
I would promise you that Single Minded Fury post I've wanted to write for months now, but until some raid boss somewhere decides to drop me a second weapon, it's not likely to happen. So I have no idea what next week will bring us.
At the center of the fury of battle stand the warriors: protection, arms and fury. Check out more strategies and tips especially for warriors, from hot issues for today's warriors to Cataclysm 101 for DPS warriors and our guide to reputation gear for warriors.