Yeah. I guess gestalt is just gestalt, getting a bit wierd is what it does, and in the end a fighter who can be useful out of combat is a pretty good thing.
For the regular characters... I can't see anything broken yet that doesn't already exist in other forms (like that practised spellthief whatnot). The Chameleon'll probably make a better fighter and barbarian than the normal fighter and barbarian without very much effort thanks to the apt. bonuses to attack and damage and ability bonuses that can match a barbarian's.
Hmm. I dunno about the apt. bonuses, but maybe you could make it that the dual ability bonuses cannot apply to the same type of stat (eg: Physical/Mental) That might stop making the Chameleon outshining the barbarian entirely, at least. Or it might be pointless.
Or maybe the Chameleon doesn't need fixing, and its just that the fighter-types are weak. I dunno.