Killing Obi Wan was the right decision though. For the first time i read the version where he lives and he does nothing of worth after the death star. His death on the death star is critical to give the film emotional weight. Luke loses Ben, and he grows up and joins the rebellion.
The story of the original script after the death star drags. It was absolutely essential to do what they did. The same way cutting all the stuff with Luke and his friends on Tatooine and going straight to the droids was the right choice cinematically as well.