First, a quick reminder. Haste’s value comes from two things: it boosts the amount of damage you do from your white attacks (because you get MORE…duh) and it increases the amount of energy you have, both passively (via small increases to energy regen rate) and actively via additional Omen procs.
Sounds good, right? Well, there’s a few problems with that.
Haste is useless if you’re not attacking something. Again, common sense, but it bears repeating. If you have to move off-target, your mastery/crit continues to affect your bleed ticks, while your haste just sits there.
Haste is terrible for bears. May not be an issue, but if you plan on bearcatting, then you want something that can affect Savage Defense, which means mastery. (Crit used to be nice, but is now devalued in bear due to the 2pT13 set bonus.)
Extra energy regeneration increases rotational difficulty. Ah, here’s the most important one. The cat rotation is very dynamic; you’ll have times where NOTHING is up, and you have to quickly execute your priorities to get everything going. You’ll have times where you need to dump energy ASAP to use Tiger’s Fury optimally. On the flipside, you’ll have times where you’re sitting around waiting for energy to regen.
The issue? Well, as haste increases, you have more #1 and #2 situations, and less #3. In these situations, fractional time matters. (What do I mean by this? Well, if you’re just waiting for energy to regen, you can use that Shred at 60 or 80 energy, it’s not really a big deal. If you’re trying to start or restart bleeds, each bit of delay starts to take away from uptime and thus damage.) This is where in-game reality starts to diverge from simulations; Mew doesn’t have to deal with raid mechanics, crazy raid leaders, or out–of-game interruptions; all of which will end up causing you to spend more time at energy cap, which also makes haste less than useful. Ultraxion is a good example of this; relying on Mangle instead of Shred requires a few more keypresses, since Mangle uses less energy.
So, what am I saying? Yes, in sim theory, all the stats are roughly equal. In actuality, though, the priorities that make it easier to play perfectly, such as capping hit and expertise, and minimizing haste, will increase your DPS the most. What do you think?