true that hip hop music often exhibits a simple loop, that's repeated throughout the song, but with a hip hop band one has the capability to be creative and exhibit interesting forms of the instrumentation aspect of it. see the foundation (jon jon brings some badass bassline) and crown city rockers. with the roots stuff too you hear the solos (kamal at the end of break you off, the guitar at the end of what they do, melting pot etc.). it's not impossible to be non-repetative with hip hop music. i think it gets boxed into something that can't stick around that simple loop.