You cant seem to separate personality and character from the technical written word and its presentation.
He had a larger than life personality, but he didnt have the technical bars and delivery system to match, he didnt have that flow and mic presence to match his public image. He relied more on his image and personality to get him through a track, so you know it'll at least be emotionally hype and from the heart. You said it yourself, he's not a 'witty' 'quotes' type rapper, and thats it. He doesnt leave a lasting impression on you after the track, he doesnt have you rewinding tapes to hear that amazing line again, something the other GOATS all have in common. The message is his personal opinion on a subject and has absolutely nothing to do with how good you write and spit it out.