Islam contradicts Muslims human made religions, like Sunna, Shiites and Sofism. Sunna in particular, has tarnishing the religion of Islam by its Shareeah , , Jihad, and its  religious state, as we see in the Saudi Kingdom and the Taliban state . As a matter of fact, Sunna is the ardent enemy to Islam.   The question should be: What would the Muslims be like without Sunna? The answer is: Muslims will be real Muslims without Sunna. Muslims will be civilized without Sunna