If by this you mean a rapper that brings raw, street energy to the mainstream while being as popular as the biggest rap artists at the moment, then it'd be welcome.
The downside to it is that people seem to get tired of it quite quickly and end up moving on. DMX had a stellar '98-'00, but by '01, people started to move on. Then there was 50, who had a stellar '03-'05, but by '06 people were already moving on. To a degree, there was The Game, but he too didn't sustain much longevity.