Well let's face it....
99% of his talent is in his ability to showcase himself.
Light your guitar on fire, play behind your head, smash your guitar, play with your teeth..etc etc...
As far as talent goes... he was able to play from the heart (which means get into what he was doing without flubbing up cause he knew people were watching)
but he was an adequate player at best.
The appeal was in his showmanship. To guitarplayers he showed a new way of overdriving the guitar. For audience members, he showed that he could trick people into thinking he was better than he was with all his gimmicks.

And yeah... if he hadn't died, he'd be an nobody right now.