I must admit, I don't really like the idea of Firebending getting magma/lava... It doesn't really fit them, or their style... I always used to love the fact that Fire got Lavabending, but now, it just seems unfair...
This is what I think should be under Earthbending:
Rock, stone, mud, dirt, sand, clay, glass, crystals (and gems), metal (ALL metal) and magma/lava... That seems fair.
Even though Fire is still (in my opinion) the MUCH, MUCH better element, I think things would be better fitted that way... And Fire could get some new techniques aswell.