[quote=Sloth]
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."
[/quote]

Right, I was thinking about the Pre-Roku Avatar, though I could've sworn Sozin had some control over it but I'll have to rewatch Series 1 to see why I'm remembering it like that. But yeah, the problem I had with Ghazan's lavabending (which was more magmabending if you ask me) was how does an Earthbender heat up Earth to turn it into that? What are the fundamental mechanics behind it? Earthbenders don't deal with temperature but mineral content. Again I think it was poor hindsight on the writers part with them making characters powerful enough to fight the Avatar (and win) but without explanation of their ability.