I don't necessarily disagree, but I guess my point is that simply improving the defensive rebounding wouldn't really move the needle that much for this team unless you're adding a guy who can also help you in the pick and roll and near the rim without sacrificing the integrity of the perimeter defense.
Worth noting that at least going by stats, the C's defensive mediocrity mostly comes from rebounding.
We are 7th in opposing eFG%, 15th in turnover% and while we're 25th in opposing free throw attempts per possession the real outlier is the defensive rebounding. We're actually good at getting other teams to take bad shots, and while we're not great at defending without fouling, it's not bad enough to make up for the shooting percentages. If we could have acquired a guy like Noel who I personally think wouldn't have made us significantly better or worse on defense than we are now I think the rebounding would have made a huge difference on our overall defense.
The question is does that kill you on the offensive end of the floor. It may well be that it does.
I think Noel would have improved the team.
I didn't really think so last year, when offense was the problem, but Noel definitely helps you defensively. He's not a great rebounder, but even so, I think he would have helped there, too.
All of that said, trading for Noel carries a pretty significant opportunity cost, in that keeping him would more or less preclude the Celts from going after a max or near-max free agent this summer.
So if the question is, "Does Noel improve you enough this year to be worth giving up on trying to get a max-type FA this summer?" I think the answer is definitely NO.
You could also ask if acquiring Noel just as a half-season rental, in light of what it ultimately cost the Mavericks to get him, would have been worth it? I'm more agnostic on that point, but at the end of the day I don't think Noel gets the Celts past Cleveland, possibly not even the Raptors, so I'm OK with Ainge deciding not to give up any significant assets to get him.