If he means over rated than the only ones I can with on this list are Springsteen, Lou Reed, David Crosby and Frank Zappa. I won't even consider Phil Spector as he was not a musician or part of the classic rock scene.
I never got the Frank Zappa-is-a-musical-genius thing. My room mate in college was huge Zappa fan so I heard damn near everything he did through 1982. Ugh... to say the least. He even drug me to one of his concerts. It was the only concert I ever walked out of.