It's still an AoE world
Wrath heroics still have little to do with strategy or encounter mechanics, and everything to do with speed and AoEing down trash. When your typical bosses die in under 15 seconds, you're really optimizing your performance for the trash, not the bosses.
To maximize your heroic performance, you really want to be as efficient as possible at slaughtering your way through giant pulls at breakneck speeds -- and be able to do this without pulling aggro, of course. This means dealing with multiple targets as efficiently as possible and managing your focus.
The heroic specs of choice
Let's be very clear on something right up front: Every single hunter spec is just fine for running heroics. You can do well in all of them.
That said, if you're really interested in doing as much damage as possible, you want either MM or SV.
Survival hunters' big advantage to heroic-running is the Serpent Spread talent combined with Improved Serpent Sting. This lets them Multi-Shot for a heck of a lot more damage than a normal Multi-Shot and DoT up everything hit, as well. This is a strong ability that gets stronger the longer the mobs actually stay alive.
Marksman's advantage is not Bombardment, as some might think, but instead Rapid Killing and Rapid Recuperation. With these talents, MM hunters can maintain almost limitless focus on trash as long as they're sneaking in that killing blow. MM also squeaks out a bit more attack power with the Marked for Death talent conveniently popping up Hunter's Mark without wasting a global cooldown.
The sad state of Multi-Shot
To be completely frank here, the loss of Volley hurts. Volley was better than the new Multi-Shot in almost every way. The only advantage that Multi-Shot has is that it is an instant shot, so we can fire it on the move, which is occasionally helpful.
Here's the big thing that you have to wrap your head around: Multi-Shot's damage sucks. I'm serious. It's not enough just for you to hear it; you need to embrace it, to truly feel it and understand it in your core. Much like an elf, Multi-Shot's damage makes you want to throw it in a deep pit, build an outhouse over it, and then invite the entire Horde over to party.
Look at it this way: Arcane Shot does four to six times the damage of Multi-Shot and costs nearly half the focus. So for Multi-Shot to be worthwhile, you really need at least six targets -- and preferably many more. Yeah, Multi-Shot is that bad. The only exception here is Survival, whose Multi-Shot does several times the damage of any other spec. For SV, Multi-Shot is certainly worthwhile at three targets.
Trap Launcher to the rescu... er, never mind
With the Trap Launcher in the game, we have the ability to toss Explosive Trap into the mix for more awesome AoE. We can stand back at range and just lob that sucker in there and cook them all!
Generally, don't bother.
Explosive Trap is actually surprisingly good AoE damage; however, because most of its damage is the DoT, it requires the mobs to stay alive for a while. In heroics, that doesn't happen so often. On top of that, the Trap Launcher is still pretty clunky to use, sucking up more time than it should since we can't one-button-press macro it. Use Explosive Trap on exceptionally large groups of mobs or on groups of four or more that are going to be around for a while.
The secret hunter rotations
Your heroic trash rotation is very different from a boss rotation. If you're BM or MM, your rotation is this: Arcane Shot.
That's it. If it's a big mob that's going to be around for a while, go ahead and put Serpent Sting on and put up Hunter's Mark only if you can do so before combat. (MM doesn't need to worry about HM, of course.)
Basically, you're just going to Arcane Shot everything until you can Kill Shot it. As MM, your goal is to get that killing blow in so you can instantly regen 50 focus and move on to your next target. With a bit of luck, you'll never even have to fire a Steady Shot. As BM, you'll need to Steady Shot a lot, which is painful because half the time, the mobs will die while your Steady Shot is casting.
SV plays a bit differently in heroics. As SV, your goal is to Multi-Shot any time there are three or more mobs. If you've got a big pack, you'll want to spam Multi-Shot as much as possible, but for pack of three to four, you'll want to toss on just one Multi-Shot and then alternate between Arcane Shot, Kill Command and Steady Shot.
As SV and BM, the biggest challenge in heroics is maintaining focus levels with so few opportunities to Steady Shot; MM rarely needs to worry about this. If mobs are living long enough for MM to need to use Steady Shot, they're probably living long enough to get off those Steady Shots. This is why I personally prefer MM in heroics; the nearly endless focus lets me maintain high DPS without stopping, resulting in better overall DPS.
We now have the ability to summon one of four pets, which means we should give some thought to what selection we want to bring with us into heroics. As always, if you have an emotional attachment to some particular bundle of pixels, have at it. These are heroics, and they do not require absolute optimization.
But if you do want to contribute as much as possible to the party, you'll want to bring the best buff selection you can. First of all, you generally don't want to bother with pets that provide single-target debuffs or defensive buffs (things that help you or your tank survive). The single-target debuffs (which are a bit bugged at the moment) won't be applied to all your packs of trash, and the defensive ones are simply not needed in Wrath heroics.
Instead, focus on pets that provide DPS buffs for your party. This includes the strength/agility buff, the crit chance buff and the burst haste buff (if you're BM).
Never forget to misdirect
As obvious as this seems, I cannot overstate the importance of using Misdirection on every pull for which it's available. Tanks are struggling a bit as they learn their new mechanics, and of course we still grossly overgear these dungeons. As always -- always -- if you pull aggro, it is your fault!
Yes, always. Even then. Even when the tank is doing that stupid thing, it's still your fault.
Keep in mind that our Misdirection has changed slightly, and the transferred threat now fades away after 30 seconds. This shouldn't matter much, as I can't remember the last time I fought something in a heroic that lived more than 30 seconds, but if the fight is going long for some reason, don't forget to FD before your MD runs out. (As a point of clarification, after 30 seconds, the threat from MD vanishes into the ether. It does not transfer back to you -- it just goes away.)
Scattered Shots is dedicated to helping you learn everything it takes to be a hunter. Our Scattered Shots Resource Guide takes aim at everything from improving your heroic DPS, understanding the impact of skill vs. gear, and getting started with Beast Mastery 101 and Marksman 101