if all things are equal frost mage will win if they know how to play as one
fire really can only win if the player of the frost mage sucks or the fire mage has such better gear than the frost mage by a huge margian ie a just turned lvl 70 frost mage vs a lvl 70 fire mage who has all the kara drops or full arena gear (which he probably got as a frost mage lol)