Luther Vandross
3
He was definitely pop for most of his big hits, but his roots come from R&B & soul. I am not saying he was a pop singer (he was definitely from R&B), but he may remembered more for his adult contemporary image by the voters. Best case is for the voters to cast a sympathy vote his way, like with Bobby Darin (who had a similar rock background, but went pop later), but the same didn't happen for Barry White, who also died early.