Was gonna say Nas, but that would end up as a Nas album with DJ Premier on production instead of a group project. Whoever it would be, it'd have to be someone capable of not being too wordy or intricate. A conversationalist with a well rounded outlook on life capable of rhyming about various subject matter.
I was thinking maybe Ras Kass, or General STeele from Smif N Wessun. They both can get real technical with the verbiage, but are also capable of conversing in layman's terms too.