I can't say that I didn't see this one coming. The Blizzard developers announced at the last BlizzCon that we'd seen the last of armor penetration and attack power, with the focus in Cataclysm being the simplification of stats. Eyonix recently posted a complete summary with all of the expected changes, and there's a lot to be digested. A few of our offensive stats are disappearing, the remaining stats are having their effect shifted, and all of our critical strike-based talents will see a nice bonus in PvP.

To top of all of these changes, Blizzard's throwing us a few bones that will have us excited regardless of what happens. The idea of 'weapon skill' is going away, so we'll be able to use any allowed weapon right from level 1, and we no longer need to grind up each weapon skill as we shift our focus. This should make swapping weapons while leveling quite a bit less painful, and will ensure that all weapon upgrades are usable right out of the box. Read on for details on the stat changes.

Let's talk about what's disappearing from gear first, and then sort out what's left:
  • Attack Power - Don't fret, they're doubling the AP we get from agility (2 AP per agility, instead of 1 now). This will ensure our AP stays in the thousands.
  • Armor Penetration - No more ArP cap to worry about, no more worries about needing an ArP trinket to make your combat build viable, and no more ditching gear as Mutilate because ArP was clogging up the loot table.
That's really it. The lost AP will be found again in agility, and ArP will be replaced with haste and crit. We may still get some ArP via the mastery stat or various talents (like Mace Specialization), but it means that we'll have one less stat to juggle on our gear. Having ArP gone cleans up our loot tables and ensures that a piece of leather will be valuable for both assassination and combat builds at the same time.

Here's the changes to the remaining stats:
  • Haste - Haste will start yielding increased energy regeneration. Expect Focused Attacks and/or Combat Potency to disappear or be completely rebalanced, as these basically served the purpose of allowing our energy regeneration to scale with haste. Blizzard has already cemented the idea of 'quick OH' with the recent Deadly Poison changes, and we'll still want a slow MH for powerful specials. The usefulness of these two talents has expired, and with Haste naturally increasing our energy regeneration, these are just vestigial talents.
  • Agility - Agility will give us more attack power, though it may also give us less crit to balance it against the other stats.
  • Hit / Expertise / Critical Strike Ratings - The trio of ratings will still be around, though Blizzard promises to make it far more difficult to cap them in Cataclysm, which means we'll be focusing on a balance of the three instead of simply capping all of them. Hit will be particularly difficult to cap, as the hit cap required for a given tier of content will change as we get into harder and harder raids (for example, fighting level 84's instead of 83's).
Blizzard says that we can expect a ton more Stamina on our gear as well, which will definitely help with some of our PvP survivability issues. Unfortunately, everyone else's Stamina is also going up, so expect far fewer 'quick kills' than you're used to. If you currently have AP on your gear (and you do), it'll be auto-converted to agility in Cataclysm. If you have ArP on your gear, it'll get swapped with haste or crit. This means that there's no reason not to stack up whatever gear you can, as it will all be great for leveling to 85. Blizzard has also talked about swapping the colors of certain gems, including moving hit rating to the blue gem category. This would be a huge boon for us, as we could safely nab more socket bonuses without sacrificing DPS stats!

We'll also see the addition of the 'Mastery' stat, which will give us perks based on our talent builds. This should ideally buff our 'best' stat, and will provide a useful tool for balancing DPS (changing the amount of benefit Mastery yields). It's designed to keep the warriors off of our leather gear, and to make sure that each spec has its own flavor and specialty. Based on what we saw at BlizzCon, things like added poison damage and armor penetration are likely in the works.

Lastly, we'll have the ability to 'reforge' gear, by swapping one stat for another. The details are still largely unknown, but expect reforging to help you stay over/under your various stat caps while also limiting the amount of gear that gets sharded on a weekly basis. It's too early to tell how powerful it will be, and so we'll have to eagerly await more details on how the process will work.

World of Warcraft: Cataclysm will destroy Azeroth as we know it. Nothing will be the same. In WoW.com's Guide to Cataclysm you can find out everything you need to know about WoW's third expansion. From Goblins and Worgens to Mastery and Guild changes, it's all there for your cataclysmic enjoyment.

This article was originally published on WoW Insider.

Cataclysm: Stat and system changes for resto shaman