There are certain things that George Lucas has done that I don't like, but for the most part, I'm more forgiving towards him than most people. As far as the changes in the Star Wars movies are concerned, newer generations of fans will be more accepting towards it. I think a lot of older fans hated the changes simply because it's not what they saw when they were younger. However, if it were your movie franchise and you had complete say about everything, who's to say you wouldn't do what Lucas did? It's easier to look at things from the perspective of a fan with nostalgic memories than it is to look at it from the perspective of the creator of the franchise.
Also, Star Wars fans seem to have a memory too. In Episode IV, a lot of people back in the day hated R2-D2 and C-3PO. In Episode V, a lot of fans hated the fact that Yoda, the Master of all Jedis was a little green puppet. In Episode VI, a lot of fans hated the amount of puppetry that was used. However, fans are very accepting of all this now. I think the prequels in time will become more accepted as well.
As far as Lucas is concerned about retiring, it's not just fanboys that are making him feel disgusted. It's Hollywood itself. Just look at the latest release from Lucas Films. They had to finance the film themselves and while 20th Century Fox is distributing the film, almost nobody has been marketing it. As much as he has always hated Hollywood, George Lucas has done so much for Hollywood, only to have them not do anything in return for him. That's terrible.
Oh, and one more thing. Even with all the changes and color corrections and voice dubs in the Star Wars movies, they are essentially the same movies. That being said, what would you rather have. modified versions of older films or mediocre remakes?