I was Arcane/Fire for most of my leveling. When I joined my guild I respeced to a deep fire raid build (10/48/3). About a month ago I went full arcane, and I gotta say I LOVE IT.
The damage out put is equal too or greater than what I was doing with fire. With Arcane Missiles I'm normally doing 800 dps per tic. X5 ticks would make a full AM round about 4.5k dps, if none of them crit.
I was getting only a little over 3k with Fireball (3.5 sec. cast) 4k with Pyroblast and that took 6 sec.
Since each AM tick has a chance to crit (about 1.5k on crit) I sometimes do 7.5k damage in 5sec.
Also with Arcane Focus, I only need 76 spell hit to cap instead of 164 like Fire or Frost. That way I can put more focus on Crit Rating and Spell Haste. Giving me a greater chance to crit and/or more DPS per second.
While AE is the weakest of the AoEs I find it the most useful. Flamestrike is ok, but its really only good for a quick burst of damage and the 3 second cast time just isn't worth the wait and the range sucks. Blizzard, which I find to be far better than FS (especially with the range and damage), can be interrupted and really doesn't do enough damage for the mana cost (although I suspect its better for a frost mage). I find myself normally using AE, especially on the Tidewalker fight (and with Arcane Impact the Crit chance increases by 6%).
Normally I'll pull with AB, and then AM the rest of the time and even give a Fireblast near the end (still a very useful spell for the instant damage). Mobs fall very fast, and if I turn on Arcane Power I can beat some 70 elites by myself.
If I run up against a mob that is Arcane resistant I just start spamming Fireballs and Fireblasts at them. I've noticed that even after respecing my Fireballs are still averaging about 3.2k damage. So I really haven't lost that much Fire DPS though respec.
Talents like Arcane Fortitude (Increase Armor by 100% of Intellect), and Arcane Mastery (Increase spell damage by 25% of Intellect) add more usefulness to the Intellect stat than just more mana and crit chance. And, Arcane Mind (Increase your intellect by 15%)gives you even more intellect to help out.
All the other talents are great for helping with damage too (lots of them either increase DPS or increase Crit Damage)
Also, because AM can't be interrupted (thanks to Improved Arcane Missiles), and the short casting time of AB, I'm outputting much more damage in PvP.
There are only two downsides to being an Arcane mage. First is the Mana drain (Arcane spells are expensive even with the right talents), and 2)The range of AM and AB is only 30 yards, 10 less then Fireball, Pyroblast, or Frostbolt. So I've had to stand closer to mobs, which gets a bit risky in raids and 5-mans. Nothing that can't be (and usually is) handled, but sometimes there is a problem with mobs being pulled out of my range so my dps suffers while I try to move closer.
All in all I say that Fire is good for PvE leveling and raiding (but is shit for PvP).
Arcane is great for Endgame Raiding and overall damage output (and is actually a good spec for PvP; I do amazing damage on other players in BGs). You just need the Int and spirit from the elite gear to help with mana regen to really make it work.
Frost owns at PvP because of its Rooting skills and Elemental Pet, and it is good at soloing because of its increased defense and the Pet (although its not optimal for raiding when you need high DPS output).
The damage out put is equal too or greater than what I was doing with fire. With Arcane Missiles I'm normally doing 800 dps per tic. X5 ticks would make a full AM round about 4.5k dps, if none of them crit.
I was getting only a little over 3k with Fireball (3.5 sec. cast) 4k with Pyroblast and that took 6 sec.
Since each AM tick has a chance to crit (about 1.5k on crit) I sometimes do 7.5k damage in 5sec.
Also with Arcane Focus, I only need 76 spell hit to cap instead of 164 like Fire or Frost. That way I can put more focus on Crit Rating and Spell Haste. Giving me a greater chance to crit and/or more DPS per second.
While AE is the weakest of the AoEs I find it the most useful. Flamestrike is ok, but its really only good for a quick burst of damage and the 3 second cast time just isn't worth the wait and the range sucks. Blizzard, which I find to be far better than FS (especially with the range and damage), can be interrupted and really doesn't do enough damage for the mana cost (although I suspect its better for a frost mage). I find myself normally using AE, especially on the Tidewalker fight (and with Arcane Impact the Crit chance increases by 6%).
Normally I'll pull with AB, and then AM the rest of the time and even give a Fireblast near the end (still a very useful spell for the instant damage). Mobs fall very fast, and if I turn on Arcane Power I can beat some 70 elites by myself.
If I run up against a mob that is Arcane resistant I just start spamming Fireballs and Fireblasts at them. I've noticed that even after respecing my Fireballs are still averaging about 3.2k damage. So I really haven't lost that much Fire DPS though respec.
Talents like Arcane Fortitude (Increase Armor by 100% of Intellect), and Arcane Mastery (Increase spell damage by 25% of Intellect) add more usefulness to the Intellect stat than just more mana and crit chance. And, Arcane Mind (Increase your intellect by 15%)gives you even more intellect to help out.
All the other talents are great for helping with damage too (lots of them either increase DPS or increase Crit Damage)
Also, because AM can't be interrupted (thanks to Improved Arcane Missiles), and the short casting time of AB, I'm outputting much more damage in PvP.
There are only two downsides to being an Arcane mage. First is the Mana drain (Arcane spells are expensive even with the right talents), and 2)The range of AM and AB is only 30 yards, 10 less then Fireball, Pyroblast, or Frostbolt. So I've had to stand closer to mobs, which gets a bit risky in raids and 5-mans. Nothing that can't be (and usually is) handled, but sometimes there is a problem with mobs being pulled out of my range so my dps suffers while I try to move closer.
All in all I say that Fire is good for PvE leveling and raiding (but is shit for PvP).
Arcane is great for Endgame Raiding and overall damage output (and is actually a good spec for PvP; I do amazing damage on other players in BGs). You just need the Int and spirit from the elite gear to help with mana regen to really make it work.
Frost owns at PvP because of its Rooting skills and Elemental Pet, and it is good at soloing because of its increased defense and the Pet (although its not optimal for raiding when you need high DPS output).