Lucas to me has always been a better producer and storyteller. If you watch the prequels, I love them because they are Star Wars, but you can see his flaws as a director. He is a great storyteller, the whole Star Wars universe is so unique and interesting. He is also good at pushing the envelope for special effects. Every movie gets better with the use of CGI (though some people don't like too much CGI, and I respect that). He is trying to push all-digital film to movie theaters, so in a sense he still is a pioneer.

I look at it this way, George Lucas is a talented man, but he is not a genius at everything. The Empire Strikes Back, IMO, is the best Star Wars movie, because it had the most collaboration:

Lucas wrote the overall story

Lawrence Kasdan & Leigh Brackett wrote the screenplay

Irvin Kershner directed

Gary Kurtz produced

Lucas executive produced

John Williams did the music

He had everyone who was on the picture at the top of their game. No clunky dialogue, he had good screenwriters. No bad acting, Kershner got great performances out of the cast. No kiddie stuff, Kurtz knew where to draw the line. Awesome score, John Williams of course. And finally, George Lucas overseeing everything to capture his vision. PERFECT MOVIE.