Small but important changes
The actual changes to arms in this patch were very small. Let's take a quick look.
Improved Hamstring now reduces the global cooldown on Hamstring by 0.25/0.5 seconds in addition to its current effects.
Juggernaut no longer adds 2 seconds to the Charge stun, but instead lowers the cooldown of Charge by 2 seconds (to 13 seconds total without the glyph).
Lambs to the Slaughter now causes Mortal Strike to refresh Rend in addition to its current effects.
Strikes of Opportunity value per point of mastery has been increased by 10%.
For pure PvE damage, only the Lambs to the Slaughter and Strikes of Opportunity changes really matter right now. The Lambs change is marvelous because between that and Blood and Thunder over in prot, an arms warrior can now keep Rend up indefinitely. This means that you'll almost never have to refresh it, making it much easier to keep Overpower going. With Taste for Blood giving you nearly 75% crit on your Overpowers, you'll be keeping Deep Wounds up all the time, and between that and Rend, you'll be getting lots of extra rage from Blood Frenzy.
Frankly, arms is in a good place now because it's got really good talent synergy. Even a non-optimal arms build like this one
(the one I'm using at the moment) can put out solid numbers. I probably would be better off with full Booming Voice, but I just can't say no to Executioner. I'm weak.
Arms is still a fairly busy rotation right now. For single targets, you'll hit Rend once and then rely on Mortal Strike to refresh it, hitting Overpower as it lights up, using MS on cooldown and using Slam as your rage dump now that HS is so expensive. Colossus Smash you'll use on cooldown or whenever it resets thanks to Sudden Death. While it's hardly the PvP monster it was in 4.0.6 (thanks to its going down to a 50% armor reduction against players), in PvE it's still 100% and still very much worth using. With Overpower being very predictable as long as you keep Rend up with MS, you won't have much trouble getting in Colossus Smash or Slam. CS should be your first priority, although with MS now also resetting Rend, if you think it's going to fall off I'd get that MS up.
While the change to LttS that lets MS refresh Rend was more of a quality of life change (it does improve DPS, but mostly via allowing you not to burn rage to merely refresh Rend), the change to how Strikes of Opportunity values mastery per point just flat out increases damage. I'd probably still put crit ahead of mastery, but with expertise not so important for arms and hit easily capped, mastery shines and might even overtake crit in the right circumstances.
For multiple-target DPS, you're still going to want to use Thunder Clap to spread Rend around, and Sweeping Strikes, Bladestorm and Raging Calm or Inner Rage (depending on if you're low or high when the adds come out) combined with Cleave spam will become useful.
So, how about PvP?
Having done quite a few rated BGs, a ton of Tol Barad, and a few randoms along the way, I'll say that arms still works pretty viably for PvP. Improved Hamstring is a must now, and you'll be using it to maintain pressure. Colossus Smash just doesn't provide the force it used to, but at least with LttS and Juggernaut/Rapid Charge glyph giving us Charge every 12 seconds, it's possible to keep roughly 50 to 60% uptime and regain it fairly often. Frankly, with healing and resilience as effective as they currently are in PvP, I think we need to see the MS debuff creep back up or the Colossus Smash nerf rebalanced to 75%, because it can be nightmarish to try and lock down a properly prepared caster nowadays, much less kill one. You're gonna need Throwdown; don't even consider PvPing without it as arms. Luckily, it won't diminish Charge or Intercept stuns anymore.
Arms PvP isn't bad, and if you're a skilled and experienced arms PvP player, I doubt you'll suddenly find yourself unable to compete. But the Colossus Smash change really is going to mess up the chance for an average player to apply pressure when needed.
With the Maelstrom Crystal prices having dropped due to new epics from ZG/ZA and the justice/honor point purchase option, I'd recommend getting Landslide over Hurricane if you haven't already as arms. Haste just doesn't scale as well for arms, and 1,000 AP for 12 seconds just seems more attractive overall for the spec, especially for PvP where you may have to make the most of those 12 seconds. A weapon chain is also attractive, depending on how often you find yourself being disarmed. For PvE arms, Landslide all the way.
The end run
I'm not going to tell you that you can't get more damage out of SMF or TG fury, depending on the situation, skill level, gear level, etc., etc. What I am going to tell you is that for the first time since Wrath
launched, we're in a situation where you should actually look at your skill at playing the various DPS specs before you pick one.
Are you long experienced in arms? Well, I'd definitely raid with it over fury, then. The difference in maximum potential DPS for the best of the best geared and skilled players might be as high as 2k or 3k DPS, but for most players, it's much smaller. As long as you remember that you only need 8% hit (about 960 hit rating at level 85) and 26 expertise, you can gear effectively for arms. It's actually easier than either fury DPS spec.
If you're terrible at the arms rotation, don't switch to it; stay fury. But if you'd rather raid as arms and you've felt pressured to go fury for maximum DPS, don't feel that way anymore. The numbers are close enough now that you'll be better off going with what you're better at.
At the center of the dury of battle stand the warriors: protection, arms and fury. Check out more strategies and tips especially for warriors, including Cataclysm 101 for DPS warriors, a guide to new reputation gear for warriors, and a look back at six years of warrior trends.