Throughout Cataclysm, the arcane spec has been a strange beast. At the beginning of the expansion, it was solidly the worst mage spec due to the absurdly high cost of Arcane Blast. After some quick patch 4.1 fixes, it became our top-performing spec, especially if we had access to Shard of Woe. From that point on, arcane was a source of potent damage. While fire has become the vogue spec for Dragon Soul, arcane still is a very viable and desirable spec. Going forward into Mists of Pandaria, that all could change ... or the spec could be made even better.
Part of the source of arcane's potency this expansion has been due to how incredibly well the spec scales with intellect. While intellect provides the same spellpower to arcane mages that it does to every other caster, arcane mages' Mana Adept mastery makes the mana increase from intellect critical. Arcane Blast, the pivotal spell in arcane's rotation, has a static mana cost that is only based on mage base mana and not their mana after gear. Because of this, the more intellect you have means the more Arcane Blasts you can fit in at higher mana levels, meaning more damage through mastery.
No more scaling mana pools
This system is entirely changing in Mists of Pandaria. Intellect will no longer increase anyone's mana. Mana pools are becoming normalized, and spell costs are being adjusted to reflect that. (Arcane Blast is 5% of base mana on live but 1% in MoP beta.)
We're also losing the mana regeneration currently offered by Mage Armor but getting 300% increased mana regeneration through Mana Attunement. It also looks like haste might become our mana regeneration tool of choice, similar to spirit on a healer, due to the datamined ability Nether Attunement.
Spell and mechanic changes
Mana regeneration isn't the only thing changing for arcane come Mists of Pandaria. As Archmage Pants explained earlier this month, Arcane Charge has been added to arcane on the beta. It's built by casting Arcane Blast and Arcane Missiles, consumed by casting Arcane Barrage, and increases the damage of all the above abilities by 25% per charge. It also causes your Arcane Barrage to hit an extra enemy per charge, meaning your AB will be able to hit up to five targets, and it causes your Arcane Blast to cost 150% more mana per charge.
In addition to that, there are other changes to our spells, such as the aforementioned change to Arcane Blast's mana cost. Arcane Missiles is still free, and as far as I can tell, it is active all the time. Arcane Barrage has the added AoE component and has been changed to benefit from Arcane Charges. It also seems to deal higher base damage, making it an actual potent damage-dealing spell for the first time.
If I'm right and Arcane Missiles doesn't actually proc from anything, this is what I assume will be the basics of our rotation in Mists of Pandaria: Arcane Missiles/Arcane Blast will be used to stack charges. Missiles will be used any time you need to manage your mana, such as when you bursted low and need to regen or if you're trying to stay above 80% mana. Arcane Blast will still be the highest priority spell, used either in burst phases or just to do more damage.
Arcane Barrage will have two main uses. First, as always, it will be our go-to mobile spell. Second, it will be used to clear stacks of Arcane Charge, hopefully doing respectable damage in the process. It seems to be mana-free in MoP, which means ArB is the only spell in our normal rotation that costs us mana.
The real trick of MoP damage dealing is going to be figuring out the sweet spot between mana consumption and maximum damage dealing. I'm sure different combinations of blast and missiles will be used at differing mana levels; you might four stack with Arcane Blast when you're at 100% mana, or weave two ArBs and two AMs when you're approaching 80. Tactical stack clearing with Barrage will be a must, as it's a fair assumption to assume Blizzard will balance so that using Arcane Missiles at four stacks will be a DPS loss.
All in all, the changes in store for arcane have me somewhat excited. This is shocking, as I've spent most of this expansion hating arcane and wishing PvE frost were somewhat viable. I believe Blizzard has done a really good job of keeping the feel of the spec while making some nice quality of life changes and doing a good job of addressing prevailing balance issues. Now, if Blizzard would only send me a beta invite so I could actually test my theories, I'd be a happy camper.
Every week, Arcane Brilliance teleports you inside the wonderful world of mages and then hurls a Fireball in your face. Start out with our recent beginner's guide to being a mage, then check out our three-part State of the Mage columns on arcane, fire and frost. Don't forget to look at some of the addons your mage should probably be using.