The East/West fued didn't really come into the spotlight until the Tupac/Biggie murders. It may have been lingering, but until the "Suge talking shit at the Source Awards" incident and the killings, it wasn't really a big issue. Mostly just guys dissing each others styles on wax.
Anyway, Tupac didn't really change rap around too much, in my opinion, though his lyrics and delivery style were a lot better than most at the time. If anyone changed rap it was Master P and No Limit and the Cash Money guys. Changed for the worst i must add. I absolutely HATE their style but southern rap has really blown up since they came around, especially amongst teenage white girls (which I noticed the past few times I've been to the music stores),. The only southern acts I can listen to are Nappy Roots and of course OutKast...