Remaking the prequels would probably involve a complete reboot of the franchise.
The earlier drafts of Star Wars had it as Episode I, not Episode IV, and I've heard it theorized that TPM might've been the movie George was trying to make all along.
The irony is that the world fell in love with his half-finished film and had, at best, a mixed reaction to his intended vision.
Personally, my biggest problems with the prequels are that GL wrote/directed them and that they are meant to be watched with the SE, not the originals. The actual story of the PT, how Anakin fell to the dark side, the Clone Wars, and the decay of the Old Republic, was always George's to tell. Those are just minor complaints compared to the much bigger problem of George scripting/directing them himself and retroactively re-directing the OT.
In that sense, the PT isn't worth the trouble of remaking/replacing. The ST and spin-offs, which will be from new writers and directors, will probably "ignore" the prequels even if they take place within the same continuity.