As long as he puts out the original versions of the trilogy as well as THX 1138 (and maybe even Indiana Jones [wires erased] & Grafitti [opening shot]), I'm fine. I don't think he'd destroying Star Wars by introducing new stuff, it doesn't (have to) mean the previous stuff cannot coexist.

That said, I think Star Wars has run its course and it's time for Lucas to move on to something else. I'm afraid that all the success it had and even doing the prequels have taken away either the opportunity or the desire or both to work on something different. I think Lucas has talked about other ideas he's had during interviews, I'd like to see him try some of those.

(Or at the very least, something besides what happens between episodes II and III. Seriously, how much do you have to drag out that aspect of the series? Why don't we ever hear much about what happened between I and II. That spanned 10 years and why couldn't Anakin have freed his mother then? Or between the prequels and the originals, when is that going to happen?)