Bull. Lucas nearly died of exhaustion working on the original Star Wars trilogy, and was a full process man in all three movies.
He personally dirtied every prop, in order to achieve a rusty look for the Star Wars world, he and friends often made the costumes and masks by hand at home, and he micromanaged on everything from the editing room to the special effects room. The reason he was not the "director" of Empire Strikes Back and Return of the Jedi was that he wanted to free himself into taking over the complete filmmaking process and micromanage things that way. And his ideas for the whole trilogy go back to a decade, for a time when he working on and off on the script.
What made Lucas go crazy in the prequels? He wanted to outdo James Cameron for Titanic, despite the fact that he was not James Cameron and was not into the same style of filmmaking. Making a fully digital movie was purely to beat Cameron in the technical department. It was a problem of ego, and it ruined him.
That doesn't make him a capable or even competent filmmaker. He has a vivid imagination and a great attention to detail, but he is a terrible writer and director. He's a good "idea guy" but the prequel trilogy was a disaster specifically because Lucas was in direct control of everything and he didn't have anybody to kick him into line. Other films like Red Tails, Howard the Duck, even "classics" like American Graffiti reveal that he really doesn't have enough talent to compete with other directors of his generation. Maybe "hack" was a bit much, but still, I wouldn't say he has much more credibility than someone like M. Night Shyamalan.
Lucas is somewhat tragic in that there was a time when he not only had great potential but applied it to make a great movie like THX 1138, which is a direct opposite to his subsequent works. It's not simply his best movie but also one of the great science-fiction movies, yet it's often overlooked for crap like Lucas' own Star Wars or a mediocrity like Blade Runner, despite THX 1138 being something like what would have happened if Samuel Beckett wrote sci-fi. Lucas was part of that new generation of American filmmakers like Coppola, Scorsese, Milius or Cassavetes, and these guys were rather close, often discussing their projects with each other. It's no coincidence that this generation gave birth to a serie of self-conscious art films like Taxi Driver, The Killing of a Chinese Bookie, Apocalypse Now and THX 1138, to name only a few, all in the short span of a decade. One can only wonder what the hell happened to Lucas after that, because it took a while longer for others to meet their artistic demise, like Scorsese. Comparing him to a hack — in the real sense of the word, because I get the feeling it is thrown around without understanding of its meaning — like Shyamalan, who has yet to make something remotely good, is very unfair.
On the subject of Star Wars, I loved it as a kid like many did, but I find it ironic that many complain how much the second trilogy sucks while the first aged so badly. SW is awfully campy, and not in a fun way like the original Star Trek serie; Jedi isn't much better, and even worse at parts; only Empire manages to stay decent by being a nervous and well-paced action flick, but the characters are still the weak point, even if they get some form of development over the course of the movie. I'm almost tempted to say that the second trilogy is just a bit better than the first, despite being mediocre, but I guess that Empire manages to save it barely.
Any universe can be interesting and full of potential but without great characters who do interesting stuff in that universe, it's rather boring, and that's pretty much the bane of SW. By contrast I only started to watch the original Star Trek serie a few years ago and was surprised to discover how much it embraced its campy nature from the very start, which helps it to be still enjoyable today, along with the memorable cast of characters, starting with James T. Kirk. In the same vein, I found KotOR 2 interesting not because it was set in the SW universe or what it did with the setting, but because it has a good cast of characters. You can tell whatever story you want but the characters are still those playing the most important part in its success.