The only problem with removing the Fire Tree is some sorcs now actually use taht as their skill rotation and don't want it to go. Trust me I wouldnt mind it but if you remove it this makes them mad and it also gives them a lot of extra points the can put else so its got pros and cons.
Who cares that Sorcerer tend to use this in their rotation? The decreased Vigor rate for monks f.e. did also ruined the pre-existing skill rotation.
I wouldn't like to remove the Fire tree though, because it's still a game where you could start as a level 1 character. When you level your magician, you can 'test' the different skills and then decide whether you choose to become a Wizard or a Sorcerer. So you should have all three elements as a magician.
The 'AoV-devs' in their Colo-adictiveness however did something really -stup... I mean unwise: They increased the maximum level of Firebolt, Fireball and Lightning Bolt. That alone ruined the balance between the three elements and made the higher fire skills viable for Sorcerers as well.