Mage critique
First thing I noticed wrong with all of the Mage builds was 5/5 in Imp Arcane Missiles. The horrible mana/damage ratio that this spell has, Mages honestly shouldn't even be using this. Even when mages gain clear casting, it is still pointless to use as most +crit talents are in the Fire and Frost trees. A fire or frost spell should still be cast when gaining clear casting. To tell ya the trueth, I don't even have Arcane Missiles in my hotbars. I haven't used the spell since late level 40's.
Frost spec =
20/0/41
Imp Blizzard is used for AoE grinding. You do not want to have more than 2 points into this because the slow effect is more than the slow effect on Cone of Cold then. This means that the slow effect will now produce on Cone of Cold when AoE grinding causing your mobs to break the effect prematurely. One point in Permafrost is to make the Blizzard effect last just a bit longer as well so you do not have mobs breaking the Blizz Slow effect.
For 1 point, Cold Snap lets you Ice Block twice in a row. This is huge and awsome for agro management. Especially if you pull agro in raids on back to back fights, which sadly I have done plenty of times.
Empowered Frost bolt is like getting a free +damage item in your inventory. Mages always go after +damage items, so when given the opportunity, there is no reason to pass it up.
Arctic Reach increase the range of not only your frostbolt, but the radius of Blizzard, Cone of Cold, and Frost Nova. This means a larger area to AoE grind. Since Imp Blizzard has points into it, AoE grinding will occur (or else your wasting points in Imp Blizzard). If AoE grinding is going to occur, the larger the range, the more mobs you can AoE grind, the more xp/drops you'll get, the better off you'll be.
Counterspell should be taken up by ANY mage going that far into the Arcane Tree. I use this all of the time. I use it in grinding, instances, raids, pulling, etc. The spell is fantastic for only 2 points. Priests have to spend 3 points to get Silence so for 2 points without a prereq, this is great.