Well he dies in 94, we never get the 4th and 5th Nirvana albums, where the bank reached its peak. Hell, we may have gotten a 6th, had Courtney Love not gone full nutso, and dragging Kurt down with her. Love always has been a terrible influence on him, there's a reason why Kurts kids all love him, but openly admit they refuse to speak with her.
If Kurt died in 94, I wonder if Dave Gruhl still goes off and does his own things - Nivana's brand may have dimmed, but Foo Fighters have proven themselves very worthy heirs to the throne of rock and roll. Maybe he puts the band together sooner?
Without Nirvana to dictate the sound of rock for the mid 90s, what might come to be the big sound? Ska was big thanks to The Offspring, No Doubt and Smash Mouth, might we see that be bigger? Rap metal was what finally replaced it, with bands like Body Count and Linkin Park. Might we see something like, god forbid, alternative become the dominant sound of rock? Nickelback and Creed being the face of rock might have killed the genre.
With the death of Kurt, does Krist Novoselic still get involved in politics? The collapse of Nirvana's original lineup was timed well for his political career - he says Jesse Ventura's run for Governor what inspired him to run for the Libertarian nomination for Governor, winning against Gary Locke in a squeaker - and a lot of that was timing. a butterfly as big as Cobain killing himself might be enough to butterfly away his two terms as Governor, to say nothing of the impact it had on third party politics and drug prohibition.