No one is forcing you to post here, Icy. Go attack some Fire Giants with sneak-attack rays of frost . . .
As far as your question is concerned -- yes, of course it's broken. Any spell that can permanently give you huge bonuses to natural armor, a bonus to speed, reach, and massively up your strength at the same time -- well, duh.
Possible fixes:
1) Ban it.
2) Say that it can only turn targets into inoffensive little weenies, like rats or slugs or fish. In other words, it's primarily an offensive spell, to be used on hostiles (though being able to turn yourself into a bat or something, to do recog, is always nice)
3) Base what you can turn your target into off of the ECL of the new creature (which you can get from Soldarin's CR creature calculator, or that Dragon magazine issue on it, or whatever).
I'm in favor of #2, myself.