No, you can still have Shape Shifting, but you cannot change into anything outside the realms of reality, only into actually existing things. To begin with, super powers aren't the most logical thing, but what you produce or can change into is bound to the laws of physics. If you have shape shifting and you change your arm into, say, a weapon, then the weapon is as likely to jam as a real one, or if you change into a tiger or something, you will only be able to run as fast as a real one. Things like that. :P I hope it is not too confusing.