If only Kurt had played a blazing Phrygian/Mixolydian hybrid picked lead line over Pennyroyal Tea instead of some 3 note feedback I'd have had way more respect for him!
On a serious note, for kids my age in the late 80s/early 90s Nirvana were a revelation and opened up my eyes and ears to a whole new world of music I hadn't really been exposed to in the UK. People can argue the toss and compare Richard size about how they knew punk before it was punk or whatever, but to me punk rock was/is more about a mindset rather than a sound. Nirvana/Kurt had a huge range of musical influences and that melting pot created some stunning music and turned loads of people like me onto some truly great music.
It was almost certainly the success that killed Kurt - he just wanted to be in a cool band who made music for people who loved music like he did. Sounds like he really hated all of the hangers on, the legions of new fans who really didn't know anything about them apart from what they saw on MTV/News channels, especially the frat boy fans who were proclaiming to be fans when a few years earlier would have been calling him names in the street.
Some of their live shows were seismic shifts, some of them not great but that's the nature of the beast. But as far as not being able to hear a word he's singing, to paraphrase Wesley Snipes in White Men Can't Jump...
"Look man, you can listen to Jimi but you can’t hear him. There’s a difference. Just because you’re listening to him doesn’t mean you’re hearing him."