Idea for a magic system

I was thinking of an idea for a magic system for GURPS DF. Using GURPS Magic in DF gives me some problems. I feel that the problem is that all of the magical energy that a wizard has can be used to power ANY spell. So that makes the wizard able to undermine a lot of things especially outside of combat. What I was thinking was that there could be different types of magical energy like fire magical energy, water magical energy, earth magical energy and so on. And each of these gets restored more slowley. Thus when a wizard has no fire energy to cast flame jet or fireball then he has to use a different magical energy source like water until the fire magical energy is restored. It could also be like Ars Magica where you need two sources. To heat metal you would need fire energy and earth energy to complete the spell. To restore a petrified PC back to normal the wizard would need both life magic enegy and earth magical energy. It might be more complicated but it might help reduce the amount of spells that can be repeated over and over to undermine the game.

Idea for a magic system