I was going to say that wouldn't be as appealing of an ability, but it would be immune to status effects that way, which would be interesting to say the least.
And while you might have a case for volatility, I would counter by saying that it's strength as a creature remains constant. What element would this ability be better suited as? Gravity might work mechanically, but not thematically. Fire might thematically, but fire creatures don't have enough HP to make it work. Earth has enough HP on its creatures to make this mechanic work, and it can work thematically. I feel like I'm stuck in a catch-22 here.
