Julius Randle is a sure thing. Just like Smart and Parker, he has weaknesses, but that's not the same thing as being risky. Shaq was a bad free throw shooter. Karl Malone couldn't hold on to the ball. Nash couldn't defend.
If we really are on a total-rebuild trajectory, I'd take that deal. I'd be frustrated, because there's a lot of redundancy between Sullinger and Randle in terms of their greatest strength-battling under the basket- and their greatest weakness- defense. I don't think a better deal is coming along, though.