I was just thinking about this in the shower. If we assume that A) we don't get Durant, B) we keep Amir and JJ, C) we don't make any other trades for a starting-caliber 4, and D) IT, Bradley, Crowder, and Horford are set at the positions of PG, SG, SF, and C, respectively, then who starts for us at the 4 spot?
Cases for each:
Amir - By having Amir and Horford down low added to our perimeter defense, we are most likely a top-3 defense in this league. Further, Amir is an excellent rebounder, and he'd greatly help with our rebounding alongside Horford.
KO - While not having the defensive prowess of Amir, KO's shooting would give us an almost unprecedented amount of spacing on the floor. Think about it - every single one of our starters would be reliable three point shooters, and the amount of spacing that would give to IT would be absolutely insane. You could legitimately just stick the bigs in the corners and the wings on the wings and let IT go to work penetrating and kicking. You'd also have an absurd amount of passing and playmaking from your big positions between KO and Horford.
JJ - Jerebko offers the middle-ground option here. While not quite the defensive presence of Amir or the offensive presence of KO, JJ offers something neither of them really bring - versatility. Not only can he switch off and defend most other positions, he's also an excellent corner three point shooter that brings size and athleticism to the unit. He also has great length and is a good rebounder. He'd also allow us to have the deadly pairing of KO/Amir coming off the bench in the second unit.
So we definitely have very good options even just with this roster, guys.
Call me crazy, but I think I want JJ at the 4 for us. He seems to be the perfect "all around" type for that position that is versatile defensively but also provides the necessary spacing for IT to go to work penetrating.