The Celtics are middle of the pack in both ORebs and opponents ORebs. So we are giving up about what we are getting. I disagree that rebounding in general or O-rebounding specifically are not important. Possessions are possessions. Giving up an offensive rebound is as bad as a turnover. People complain like holy he!! every time Smart or Brown turned the ball over. Giving up an OReb has no less impact.
I am not sure if shooting a lot of 3s is good or bad for offensive rebounding. To Tatum specifically, he is our primary scorer and is not going to be in position to get ORebs, nor would we want him to be. To me, that is the issue of not having a real PF or second big on the court. What we are doing is taking off a big and replacing him with an extra guard (White). Tatum is not the guy we should have out there trying to get ORebs or playing a PF role in general.
One thing that may be true is that when a team takes more 3s, the guards may be more likely to get ORebs as the rebounds tend to be longer. I think Pritchard and Holiday are going to get their boards in any case, just by the way they play, but it does seem that shooting 3s would offer more opportunities for rebounds that a guard can get.