For ideas... well, it sounds crappy, but I advise picking up the spell compendium, start at page one and keep going until you find a bunch of cool spells that could be adapted as manifestations/aspects. Noone will ever know, unless they read this.
(Alternately, try that with ToB for more passive stuff.)
As for the dead levels... as I said, maybe get some special aspects/manifestations? Or, rather than special, generic: for example, a second level generic aspect might be fly 60' good maneuverability for 1 spirit point/round. Or charm person, or blindsense, or teleporting, or anything else like that that could apply to any of the forms.
Also, I like the idea of having an elemental, but only being able to do damage is kindof boring. What about things like burrowing, summoning winds, meld into stone, etc?
In the end, I can see this as becoming a kindof spontaneous, refluffed ToB character, but it'll need a lot more aspects and manifestations.