I've been trying to hold off commenting on mage talents for WotlK. I've already researched every tree deeply and been watching updated WotlK mage movies that people have taken the time to do testing with. Yeah the arcane deep tree is ... lol well... I like the mechanics blizzard is trying to give us with making arcane the instant cast tree, but yeah 3500 consistent crits from arcane barrage is kinda op :P Delicious... but op :P
Though over all it seems blizzard has tried very hard to put the mage tallents as such:
Arcane is the single target nuke
Fire is the AOE King
Frost is the best spec all the way around due to the CC, chance to get impact from fire, and the party mana regen from the water elemental being able to be out for 1 minute. Not to mention the chance for insta-free-fireball.
While this may sound extreamly nice for frost I frankly think it's a little retarted. It makes it so that every raiding mage worth thier salt in the group better be frost for that mana arua

. Granted the arcane tree finaly give a targeted debuff ( the arcane focus: 140 more spell damage to the target for the next 30 seconds or untill 50 charges have been consumed).
I personally will be sticking with arcane because I like the badarse factor arcane gives me (SUPER SHINY MAGE LIGHTNING FTW

ahh.. shiny...

). Arcane has finally been transformed enough to raid with (extreamly increased mana efficiency). Not to mention if you go deep enough into fire to get mastery of elements, then clear cast a arcane missile, every wave of arcane missile that crits will give back 30% of the mana cost of Arc missile :P Yummy.
Well thats my rant on mage tallents for now. Of course NOTHING as far as talents is final. Not even when WotlK will be released :P Just remember BC folks. Everyone's talents got changed in significant ways withing the first month rofl ;P