I give him his due for being an astute businessman and for bringing R&B and Soul to an under-served audience. He created an iconic show and brand. I didn't think he was much of a host though, usually sporting a rather dour expression. He smiled only rarely. And he beat his wife. Looks like that people will be singing (literally) his praises now though.
I think one person's "dourness" might be another's "low-key" style, when you're talking about Cornelius. I think Cornelius clearly emulated Dick Clark in that regard--as we all recall, Clark maintained an even tone of voice when introducing songs and interviewing acts who appeared on
Bandstand. Because Cornelius largely became big by luck, he probably felt he it would be best to do the same as Clark and not employ the "jive-talk" banter that DJs on 1960s soul stations frequently did. That, he probably reasoned, might have ruined any chance
Soul Train had in getting a large audience among whites--and getting the seal of approval from older blacks also, who were highly sensitive about stereotypical presentations in media at the time.
Be sure to see my other thread about
Soul Train's impact upon American culture.