I love KO, but there isn't a small forward in the league (or the D League for that matter), that he could adequately guard.
I would honestly start him over Sullinger if I had to choose one. KO is a better passer, a better shooter -- and actual threat from 3-point range -- and he does a better job running the floor. He can't outmuscle other 4s down low on defense like Sullinger can, but he surprisingly held his own on the boards, with very similar numbers.
I know it's blasphemous to say -- and KO doesn't have Dirk's athleticism -- but Olynyk has better numbers than Dirk as a rookie, and his per 36 numbers look very similar to Dirk's breakout second season.
I'm concerned about Sullinger's offensive game, which started to look Antoine Walker-like. You can't live with 42.7% shooting from your power forward (and a sinking true shooting percentage of 49.7%)