no matter how you try, you just can't add too many things before you have to start with questionable "elements." when we start thinking in terms of adding elements together like air and fire to make things like lightning or water and earth to make clay or mud you start to get to a point where you have to ask what the point of it is and whether or not it makes sense and if it's going to actually be used. I don't think it's that valuable as an intellectual exercise (although fun) to get to far out from basic elements. My opinion, of course.
That's one cool looking elemental planar/magic system. It's impressive how you've managed to fit it all in and it's still understandable. The associations between the elements seem to be pretty well thought out too. Nice work.