I tested various Arcane, Fire and Frost raid specs for DPS and mana efficiency. For each build I did three tests total, and compared time before mana ran out, overall DPS and average damage. I did not evocate or use mana gems or pots.
For now, Fire is rather mana inefficient, although Arcane does run out of mana faster. Frost is quite mana efficient and consistently did more dps than any other build.
I tried a Scorch build but it didn't produce as much overall DPS as a deep Fire build. It would be more suited to PvP.
I tried Living Bomb. It uses too much mana to be of any use in raiding, but overall, fire produced better average DPS if LB was kept up on the target. I think I overwrote it a couple of times before the explosion, which didn't help with seeing more accurate overall damage.
The best Fire rotation seems to be stacking Fire Vulnerability with Scorch and then Fireballing until you proc Hot Streak and throw an instant Pyroblast out. IMO, Fire is not worth speccing into for raiding at this point. Unless they make some changes to key talents instead of giving the option of retarded things like instant Flamestrikes, Fire will be fail.
Fingers of Frost is very nice. Dropping a Deep Freeze straight after the next Frostbolt increases DPS a lot, and being able to summon a Water Elemental twice before running out of mana is incredible in terms of DPS and mana regen. I kept up over 1800 DPS on the target dummy. Also, the lowered cooldowns on everything will make running heroics incredible.
Finally, I tried a 0/43/28 Elemental build to see how Frostfire Bolt held up against pure builds' main spells.
Surprisingly, I was putting out almost 2K DPS when I put Fire Blasts into the rotation. I tried it without wasting mana on them and the fight lasted longer, but my DPS dropped to about the same as frost. With Cold Snap up -- so using 2x Icy Veins in the fight (but only one Combustion) -- my DPS increased a little. I was pushing 1900-2,000 near the end of the fight.
It actually looks like Elemental builds are very viable in terms of mana efficiency and DPS, with the introduction of Frostfire Bolt -- althought the spell itself could do with a little buffing. Frost is still the strongest PVP and PvE spec, but with enough crit, an Elemental build could prove to be quite incredible. I had already decided not to go Fire in WotLK. Now, firsthand testing has completely dissuaded me from it. I think I may be Frost for a while and then switch to Elemental when I have built up decent crit gear and see how it holds up in Heroics and Raids.
As a final note, I'm not sure where Fireball and Frostbolt would fit in, but I did reduce their cast times in my Elemental build. If anyone has further insight on this, I would like to hear what other people have to say from experience. My testing was very limited and was only done against target dummies.
Gaiwyn of Proudmoore