What would've happened if Obi-Wan would've missed cutting Anakin in Ep. III and Anakin killed Obi Wan?
Then the original trilogy could not have happened, and millions of Star Wars fans would lay siege to Skywalker Ranch demanding the head of George Lucas. Yeah...that would be bad. There's certain things that I've learned about the natural balance of the universe. You never cross the streams, you never cause a time paradox, and if you want to go back in time you need 1.21 jiggawatts of electricity.
Messing with Star Wars continuity is another important aspect of the natural balance of the universe.