Not sure if you're intending to keep this Aero only, but I would say look into hybrid skills aswell. Say, a hybrid Hydro/Aero skill that makes an electrified puddle or some such. Could that work? Maybe gaining certain damage % bonus from each skillstree. Else, something like a "Static Cage", shocking/stunning whoever leaves it, sounds cool.
On another note, i've always felt that haste should've been an Aero skill.... or a "Hybrid" fire/aero skill, at least.
Great initiative either way! Always been a big fan of the Lightning element in general and I admit I felt this game lacked something in it.