Most sophisticated and intelligent musician

Let's stay with not classical musicians.
It's John McLaughlin for me.
"Kurt Cobain, he did redefine rock and roll."

Not Courtney Love?

She's been looking quite sophisticated of late.

Just kidding. I am a Kurt Cobain fan but am kind of mad at him for not sticking around.
Don't forget those who did something new, like Les Paul and even Chuck Berry.
Peter Gabriel
Frank Zappa
Van Morrison
Brian Wilson
Peter Asher
Booker T Jones
Jon Leventhal
Bob Dylan
Donald Fagen
Robert Fripp
Paul Simon
David Byrne
Thom Yorke