Perk was a MUCH better help/team defender than JO, even without the shot-blocking. And the fact that Wade and LeBron (and D-Rose) are penetrators makes me think the Cs would be better off with Perk. Perk looks bad now, but certainly no worse than Jeff Green. If Green ever pulls his head out we could be in business, but I'm not optimistic for that this year.
Then there's the "chemistry" argument. I was on a rec hockey team that went from worst to first by changing 2 guys on an 18-man roster. Two guys. And it's not as if the new guys were much better, or that the guys who left were jerks, it was just that the team just fit together after the change. No more arguments, lots of joking around. And lots of winning. A team is more (Bulls, who only have one above-average guy) or less (Lakers) than the sum of its parts. I cannot tell with the Cs what they are.