Sure damage compared to a slowing effect is diffrent, but that they both come out as the same form and its a little rediculous, i.e. the fire and ice rain.
Personally, I enjoy the juxtaposition from an atristic standpoint, but I understand completely. I see it as him having the same powers, but when he uses the power of fire they're expressed differently.
There seems to be less reason to go fire because even though you do more, it isn't that much higher, and you take so much damage that you'll probably gert more out of freezing your opponent and then hiting them with an ice rain while they cant attack back.
It's a lot more. 4 attack powers vs. 1. It's no contest, and most of those are potent AoE, so fire torchies can really screw up some creeps and rake in the XP.