I believe that Dicky is the last one to "clean-up", per se. Last I heard, he was still drinking, wife beating, etc. I can't tell you how many shows that I saw where he was in jail for one thing or another.
Besides, Derek Trucks is the best possible replacement. The kid pretty much grew up touring with the band, and has heard every song in every way it's ever been played. It is eerie the way he almost sounds like Duane, especially his slide playing. The tone of his guitar is darn close, and his feel is almost spot-on.