I really don't get Jimi Hendrix...he wasn't very smart, he didn't sound very good, and he wasn't metal. So what's the big deal? I agree that he did a lot for rock guitar, but nothing he did still holds up.
There is no one "Best Guitarist EVAR!" because that's a matter of taste...that said, I love Stevie Ray Vaughan's solos,
First of all I hope you realize just these two statements tied together is contradictory. Then Hendrix may have argueably written the first metal song. Even if you dont view it as "metal" he was the root. Shouldnt think of him or any of the hardrock guitarists as "rock". "rock" was that sappy stuff, top 10 played all day on the radio stuff. Hendrix and Page did not fit the "rock" catagory. Then you better read some lyrics and listen to his double stop rythmn technique before you determine brain wave capability. Then you need to explain that if he "didnt hold up" why the greatest guitarists living today have all played tributes and covers to him. Explain it to them not me.
Then you mention the chipmunk twins of dragonfarce. Even as fast as they honestly are live they dont play anything that wasnt already done 20 years ago. Creativity is essential to qualify for "best of" and Hendrix had it, dragonfarce doesnt. That will always "hold up"
Now Ill agree with you, Kobain did the world a favor, you figure out which one. The other new 90's heavy pop bands (AIC, STP, Soundgarden) were a good thing though. Pop metal was getting and had been really bad. Kiss sucks. Motley Crue had like two decent songs. Dream Theater was another band that was turning heads during the grunge movement and set the bar for what has become current progressive metal and their early works still "hold up" today.
You give Iommi credit but want to take it from Hendrix. I'll agree that Iommi was very important but he was a primitive power cord player, comparitively Hendrix owned the fretboard and had many tecniques.
Side note: Zakk Wylde is great but he didnt invent "pinch harmonics" a simple Texas blues/boogie player, Billy Gibbons was all over that shit in the early 70's. The pop metal players consistently used them. Zakk has his way though.
Being amounst the greatest is as much about what you brought to the table as it is how "fast" or flawless you are.