What I would have liked to have seen: Kurt divorces Courtney, breaks up Nirvana, and enters rehab. Cleans himself up, and because he's out of the public eye, he's able to stay clean. Maybe pump out some solo work.
Pearl Jam was able to successfully slough off the casual fans, and pretty much just focus on their core fans. Nirvana *could* have tried to do that, but I don't know if it would have worked. Kurt would have still been the focus, which wouldn't have been conducive to cleaning himself up.