[quote=Gowi]Also, Sozin and Roku (as well as a previous bender) showed lavabending options as so turning it into an earthbending form didn't make much sense to me. But that's a small gripe.[/quote]

Actually all Sozin did was redirect pure heat from a volcano via firebending, which makes sense since Firebenders have been shown to manipulate steam and so on. The only bender shown to actually manipulate lava before Ghazan and Bolin was an Avatar in a flashback who made a trio of volcanoes erupt. To me, it seemed to be a clear example of "Only the Avatar can do that." since lava came across as a mixture of both Earth and Fire. Granted, waterbenders have been able to control all phases of the element (ice, mist, etc.) so Earthbenders doing something similar isn't horrible (IE: Sandbenders, if that counts at all) I just didn't enjoy what I interpreted as "Avatar only bending" being given to a villain and thrown at a mediocre character because "Well apparently he can't metalbend."