Compared to the old Storm Shaman, or the more recent Molten Ravager, this is quite weak. You have a defender with a "worse" mana cost only for +0/+1... I'd play one of them, if I need it...
However, I'm not sure if I would play Wall of Lava, like Serev said. When you play a wall at the 3rd turn, you need a great thoughness in order to block without problem, without spending mana that you need to play other spells... A 1/3 is too weak to block, so you have to spend mana every turn to use it.
1/5