Seriously. This show is in its eighth season and the show was built around the interplay between Sheen and the rest of the ensemble. I think to bring in John Stamos (or anyone, for that matter) would be a bad move.

If they absolutely have to continue, spin Alan off into his own show, moving him out of Charlie's house and into his own place. Maybe Alan can catch a bit of luck professionally, just enough so he can get his own place and start having misadventures in dating while raising his teenage son.

But the show as we know it is over and should be laid to rest.;)