Just my two cents, take it for what it's worth, but I don't think some out there stuff would be too bad. 

Most people will go for simpler energy-based powers, but being able to bend a little for something that is well thought out wouldn't be too bad. It puts the burden on the player to come up with something acceptably fleshed-out, and given that we're discussing a shounen setting... That sort of thing wouldn't be too far outside the genre norm.

On an unrelated note, do you have any idea what the big fields on the CS might be? I'm starting work without one, but I want to make sure I cover the major bases so I can fit it all into the actual CS when it comes up.