Speaking of consistent internal logic, could you please allow shifter forms that can speak (parrot) to cast spells? As it stands you get the "You can't form the words" message.

That ignores the somatic component of spells (which is why binding a spellcaster's hands is a big deal), which would require the form to have dexterous limbs as well.

THIS I would consider cosmetic. We could change the echo for speaking forms, I suppose.

I guess the pronouncation matters a lot as well, so parrot, while being able to pronounce something "resembling" a spell, would never be able to pronounce it correctly in order to draw mana.