I am going to agree with you both. His problem is he is a tweener. He is too slow for many PFs but he gets pushed around by real centers because he isn’t very strong. I don’t think he ideal for either position. I think he is straight up a match up guy which makes it hard to play him sometimes.
Fair, bigger players do bully him in the post, he's more of a help defender. But I think his biggest faults are his inability to keep guys in front of him or rotate on the outside and his really sloppy ball handling whenever he gets the urge to dribble.
His only plus outside of the post is that he can make threes, but he's really inconsistent and he needs to be in the right spots. Play him at the 4 and he will end up taking a lot of corner threes... and he's reeeeeally bad at corner threes. Meanwhile, he is flat out elite at inside scoring, despite his light weight.
This shot chart paints stark picture of his strength and weakness as a shooter.
Bol Bol has shot 55.0% (408/742) overall and 32.7% (66/202) from three in 144 games in his career. (Shot Chart)
www.statmuse.com
Moral of the story, as a 4, the negatives vastly outweigh the positives. At the 5, he can do a lot of good, especially if you use him as a top of the arch shoot or roll player. He isn't a pick and roll guy because he doesn't set good picks. He isn't a physical player, this is a problem for him as a 4 or 5.
His biggest problem at the 5 is rebounding, he's real bad. He needs to play along side another guy who can crash the boards.
He's situational, he's a lot less likely to hurt you as a 4 than as a 5.