I think this would work better to balance out Natural Spell:

Natural Spell (Metamagic)
You may cast spells without a humanoid physiology.
Benefits: You may prepare a spell so that it may be cast when using wildshape. This spell is prepared as a spell of 2 levels higher, or 1 level higher when prepared with an additional metamagic.
Normally: You can not cast spells while wildshaped