Yes, Anakin saves the day, but so does Lando. So does Han in the first one. Even R2D2 does it in Empire. That was the Star Wars Style: The last minute escape/rescue. It didn't suddenly make Anakin the most important character. And the trilogy's resolution is hollow only if you don't care that Luke becomes a true Jedi, the emperor is killed, the war is won, the whole gang made it through alive and everyone lived happily ever after.