But CO, you can technically not think about the rest of the Star Wars films and just watch A New Hope on its own anyway...even with Episode IV A New Hope spliced onto the beginning. Nothing is stopping you from watching that film and that film alone. You can choose to continue or you can choose to stop at the film. The film still works great on it's own. And even in Saga terms, it works very well as the first victory for the Rebel Alliance.
The Saga can be looked upon as the story of Anakin Skywalker. That doesn't change the fact that once you get to the Original Trilogy, the main character is still Luke. He's the one we follow to Vader's end and the Empire's end. Lucas saying that the Saga is about Anakin doesn't ruin that.