Bingowings said:
Clearly Anakin/Vader was never originally the main focus of the saga
Even more to the revisionist point - it wasn't Anakin\Vader until Lucas had writer's block while trying to come up with the second film. It wasn't even a saga. It was a film that they hoped would break even. If it had been a pre-planned saga, Lucas wouldn't have hired at least two writers (Foster & Brackett) to try and come up with an idea for a second film. Their two stories aren't even remotely similar. Pre-planned? - hardly.