Most games have fire and frost specializations for mage, it's very common in many games. I hope it will be same in this game. It just makes the most sense for mage because fire mage is obv a mage specialized in dealing as much damage as possible but that's almost all they can do, just tons of damage, that's what mages are known for. Another very popular mage specialization is frost which does a lot of slows and freezing enemy so they can't move, maybe stuns too, as well as a good amount of damage, that's very popular for mage playstyle in many games.