@Nero I don't think two natures is too bad of a thing. Couple of releases require two chakra types like storm (lighting, water) and scorch (fire, wind), but they are like Junin masters when they use it. Also I think you can change your nature(?) or add onto it. Like Naruto - he added Yang release later on to his Chakra. I don't know how powerful that would be though at the current state.