Awrite, so I wrote a big post and it got deleted because I got logged out. That's lame.
So, LB, gotta disagree with your second point assessment about Olynyk -- I haven't had time to really dive into the numbers but on the face of it I think if it bears out that KO is playing better at the 5 than he is at the 4 (even if his ceiling is probably a bench level NBA player, which I believe we agree upon) it seems kind of silly to put him at the 4, although that's mostly arbitrary given our bigs.
The point that stats, particularly defensive stats, are lineup dependent is true, but I believe C18 (and he's gone on about this in other threads) is right when he points out that Olynyk's defensive deficiencies can be mostly masked if he's tasked with guarding the opposing five. That's not to say he'll turn into Omer Asik, but simply that he's less bad at guarding centers, at least guarding centers mitigates his worst qualities as a defender.
I tend to agree.
I've watched Kelly play defense in the post, and he's actually not that bad. Sure he's not a shot-blocker, but he actually plays quite physical and positions himself well - he's also very adept at taking charges. He lacks the outright length and strength to dominant on the defensive end, but from I've seen he tends to make up for that somewhat with smart positioning and strong effort.
Finally his lateral quickness (a bit of a weakness at PF) becomes a strength once he moves to the center spot - he's quicker on his feet than a lot of NBA centers.
Where his real advantage comes in though, is on offence.
When KO plays the center spot, he creates a LOT of matchup problems because the opposing center has to step out to defend his perimeter shot, and yet very few centers can stick with KO if he puts it on the floor and drives to the basket.
I lost count of the number of times last year where he caught the ball on the perimeter, and the opposing big was forced to run out to contest. KO then used a baby pump fake, put the ball on the floor, and drove straight past the defender like he was standing still. With his decent mobility and very good ball handling skills, most opposing centers just can't change directions and stick with him off the dribble.
Once KO does get in to the paint, he's a muti-dimensional threat. He's a very good finisher around the basket (68% FG inside 3 feet last year), has the IQ / court vision to make the right pass of the defense contests, and he has the ability to pull up for a jumper/floater if the defense clogs the paint.
If the opposing big decides to avoid this scenario by no running out to contest him on the perimeter, then KO can (and will) knock down open threes all night long.
I feel like putting him at the PF negates a lot of that advantage in todays NBA, where many teams now go small and play quick hybrid-forwards (like Thaddeus Young, Rudy G@y, Paul Millsap and Jeff Green) at the PF spot. Guys like that are quick enough to run out and contest Olynyk on the perimeter, and tp react and stick with him if he puts it on the floor. Yet Olynyk's lack of physical dominance (length and muscle) means he doesn't have the ability to punish the defense for putting a smaller and more agile PF on him.
Also many of today's PFs are perimeter oriented anyway, so having Olynyk draw them out on offense doesn't necessarily hurt a team too much, since they can still have their center stay inside and take care of the interior. Putting him at center forces the big man to step out, which leaves the team (potentially) without a rebounding in the middle.
I actually think this is probably a big reason why the Sully / Olynyk duo has been so statistical strong in the past. If Olynyk forces the center out to the perimeter, then Sully is going to be able to dominate the paint and out-rebound most opposing Power Forwards. Likewise on defense Sully can create just as many mismatches with his ability to overpower smaller fours in the paint.
While Sully and Olynyk aren't great defensive players, they aren't TERRIBLE ones either (at least statistically) so if they probably cause more trouble on offense than they are given on defense in most cases. They obviously lack rim protection, but that's less of an issue for us given that any perimeter players trying to get to the rim first need to get past some combination of Smart/Bradley/Rozier/Crowder/Jerebko