He does easy projects because, basically, he's lazy and likes dealing with special effects more than he likes making movies. I took a class on Lucas when I was in college, it was an auteur class, and normally they do Hitchcock or Capra, but the semester I took it, they did Lucas.
Basically he's lazy. He did the first start wars movie, and just consulted on ESB and ROJ. The stories for those movies aren't even his, they were written by someone else. That being said, he does like to be in control, he just doesn't like the day to day ---That which is odiferous and causeth plants to grow--- of directing and writing and all that other stuff.
I don't think he would ever let anyone remake or do a spinoff for 2 reasons:
1) There is no way he would let someone else's vision threaten his idea of the Star Wars universe
2) No good director would touch that project. No matter how good it was, it will never be as good as the original in the eyes of the fan boys and the director would get so much ---steaming pile of meadow muffin--- it wouldn't be worth it. Not to mention that Lucas is greedy, and wouldn't want to share in any of the licensing or merchandising revenue, or any other profit participation.
That being said, if a remake ever WERE to be made, I think the most interesting choices would be Tim Burton. He loves campy sci fi and has his own distinctive style that would definitely set him apart from Lucas. It might be incredibly horrible, but it would definitely be different and interesting. I also think Aranofsky would be good, he's good at relating characters to the aduience, and would breath life into the incredibly shallow relationships all the Star Wars cahracters have with each other.