(A little bit verbose, apologies in advance.)
I'm sure a lot of people know that Mages are not perfect at the moment, especially in the wake of the announced nerf to the Fire specialization. Below is a list of changes I believe Mages would benefit from. Feel free to comment, and pitch in suggestions of your own.
• First and foremost, the Deep Freeze issue. Frostjaw should be gotten rid of, and replaced with Deep Freeze in the talent tree. Additionally, Shatter needs to be removed as a baseline passive - the critical strike bonus can be rolled into Fingers of Frost and Brain Freeze to keep Frost viable.
• Arcane Charges need to be given their own resource bar rather than being made a debuff; this will emphasis the role of Charge management as well as prevent them from being cleared by Ice Block.
• There needs to be a way to make the Arcane rotation a little more bursty and not so back heavy in order to make the spec PvP viable. One method of doing this might be a glyph which makes Arcane Barrage refresh your stacks of Arcane Charge if cast at less than six stacks rather than clearing them. It's a tricky dilemma, but the concept is the same.
• Fire's rotation needs to be looked at, given that it's terribly hurrdurr at the moment. I suggest something along the lines of a passive that increases the damage and reduces the cast time of Frostfire bolt by a percentage every Fireball cast. This gives both a consistent source of increase as well as variety in the rotation.
• Ice Barrier needs to be made baseline, perhaps changing visually based on specialization, given the value of active mitigation and the fact that everyone is going to take it unless it is made utterly useless as a talent choice. A suggested replacement could be Illusion Mastery: Whenever you cast your Mirror Image spell you enter a state of Lesser Invisibility for 10 seconds. Again, it's not perfect, but just a suggestion.
• A glyph should be introduced that gives Frost Mages the ability to exchange their Water Elemental for increased damage, and giving them an ability that generates 2 charges of Fingers of Frost every 30 seconds, or something to that effect. Because while a Water Elemental can be cool, a lot of people despise it. If we wanted a pet, we'd roll a warlock.
• Finally, Spellsteal. It needs a cooldown, not a mana increase, and Glyph of Spellsteal either needs to be replaced or buffed to compensate.