I don't plan on raiding on my Mage.
Seriously though, which is better? atm I'm going with Frost, because I don't have the money to buy tons of +fire damage greens, and being able to AoE grind is a really nice prospect. Plus with shit like Iceblock and Ice Barrier, I'll be more resistant to gankfags.
Also, another question, I read that you only need to put 2 points into Improved Blizzard, for AoE farming. Why? Is there some bug or glitch that makes 3 points unnecessary?
This pretty much says it all. Sorry i can't resist the urge to pick on you, but you obviously saw a mage aoeing a ton of mobs and got jealous and rerolled huh?
Your question is rather loaded though. All mages, and I do mean
EVERY mage has their own preference of trees. Honestly it just goes to show how well made the mage class was, a true rarity in Vanilla and quite frankly they are
all viable for grinding and raiding. Each has their own perks and downsides.
First off, spell damage is even more necessary for frost than it is fire. Fire already does a bucket load of damage, frost, while cheap, does poor damage but really benefits more from spell damage because it's cheap. That's a moot point though because you won't need it. AoE's scale extremely poorly with spell damage. Also you take a LOT of damage aoe pulling, so stam and intel are the only stats that matter. This means you want 'of the eagle' gear. Not that that's the easiest thing to find, and anyone who knows anything will put it in for almost as much as +spell dmg, still it's easier to get a hold of stam/intel gear than other things.
You said you wanted your mage for AoEing, but you didn't plan on raiding with it. That's fine, a mage is a
great alt to have as a mats/money grinder. But if you don't plan on raiding with it, I would highly suggest rolling the class you intend on raiding with and capping that one first.
Second, AoE grinding with a mage is pretty much impossible right now because the server is so badly over populated. If there aren't a bunch of players already grinding the mobs there's (at least) one mage already there aoe grinding.
If you plan on making aoeing your thing on your mage, yes I agree you should level it that way. AoEing with a mage only looks easy. It's actually very intricate and is a high risk, high reward style of play. The slightest thing can make a good aoe pull go pear shaped really fast. Coupled with the fact that
EVER other player (including other mages) will hate you and try and fuck with your pulls, and on top of all of that, the pathing on this server is pretty bad. I've quite literally had mobs walk straight out of my aoe in all directions when they had no reason too, and some even unable to decide which direction they wanted to go.
Also an aoe grinding mage is VERY susceptible to being ganked as you almost always low on health and mana by the end of an aoe pull, and it's particularly hard to defend yourself when you have a dozen mobs chasing after you as well.
The reason many choose to put 2/3 Imp Blizzard is because the slow with the longest duration (CoC) over rides the any other slow. Me personally though, i find that mobs with the 40% slow from 2/3 imp blizzard still move too fast through it and I always go with 3/3 Imp Blizzard. It's a matter of play style and you'll figure your own style and preferences out as you learn it.
But like I said, unless you intend to raid with it, don't bother leveling a mage right now. Go level your main and come back to it after the server has calmed down and most players are playing at end game.