OK, let's asume that GL HAD an original vision and wrote the siex episodes back in the early 70s, which we know NOT to be true. So, if he had made Phantom Menace as the first Star Wars film, it would be dull and weird. First, there would be no pod racing, so it would be mostly dialogue. He would have edited the film in a slow pace, more like the first rough cut of ANH. I doubt there would even be a Darth Maul, he would probably be Vader, and the fight would be slower and more like swordfighting. There would be no Yoda, and no Jedi aliens. Palpatine would be someone younger... And the movie would most certanly flop, or not even be completed at all...

OK, so asuming he does complete the films and they become hits: they would have more of a cult status nowadays, and would be considered a weirdness of the late 70s early 80s. It would be what Tron is today. I doubt there would be another trilogy, he would kill off Anakin on episode 3.