Watch the Beggars - Solo online guitar lesson by Jeff Scheetz from Rock Solid
When I hear someone playing a pentatonic based solo but making it sound like it's not just the same old blues licks, that is when I really take notice.
That is what so many of the 70s players were doing, they were really experimenting with this "rock" thing. A lot of the 60s rock, when it started getting kind of weird and psychedelic, the guitar solos were still a bit simple and coming from a straight blues background. Then Hendrix came along and opened things up - that seemed to make a lot of players aware of the different feels that you could get from the guitar.