so a rapper needs to be fast or talk predominantly about politcally relevent topics to be good
Well, he doesn't have the sheer speed or flow of someone like Gift of Gab, or the really good lyrics of someone like Saul Williams, so I guess that makes a pretty average rapper.
that rules out like seventy five percent of my favourite rappers
Not neccesarily, but having a solid, coherent flow and good word choice certainly helps.
And that's just the rappers, with no attention paid to the beats or how catchy the whole thing ends up being.