On the one hand, I feel for Crowder. Losing his mom, getting traded, and playing our of position all season isn't easy. He seems like a good dude, so I hope he finds his way.
On the other hand, we all see Cedi, right? We all see him guarding 1-4, hustling after loose balls, getting deflections, going after boards, cutting when he's supposed to and spacing correctly? THESE AREN'T SYSTEM THINGS. They are basketball things. Nothing about Crowder playing out of position ever stopped him from doing the right basketball things.
I thought this and posted as much when the trade was made, but I don't think Crowder is a good BASKETBALL player. Tell him exactly what to do at all times on the court, and he's above average. But that isn't basketball. The guy would catch the ball on the perimeter wide open, and stand there as if someone was speaking to him in a different language. If you're open, shoot. If the defense is closing hard, attack the closeout and scramble the D. If you're not open, pass. This is literally the shit they teach you in elementary school, and he couldn't seem to do it.
Defensively, he was always going to struggle because he wasn't strong or long enough for 4s, and he wasn't quick enough for ball-handlers. He had good defensive numbers in Boston because they had defenders around him (outside of IT), but anyone who actually WATCHED them could see he was wildly overrated on that end. And putting him on the Cavs expecting him to be the defensive stopper was a recipe for disaster. But too often, he simply didn't try on that end, so I can't fully absolve him.