If you look at our main bench guys, Hauser (312 min/+20), Pritchard (294 min/+93) and Horford (288 min/+50), Hauser is the least effective in terms of +/-. These 3 are all getting to play with more or less the same rotation players and combinations. Horford has only played 12 games vs. 14 for Hauser and Pritchard so he is averaging the most per game (24 min/gm).
I am happy with what all 3 have given the team. You want bench guys to have some position versatility which they all have. You want them to take care of the ball (all have <1 TO/gm). Plus these 3 are generating additional possession with ORebs (2.6 combined), steals (1.4 combined), blocks (1.2 combined). Also, 6.6 assts per game combined, so these guys are moving the ball.
None of these guys are going to give you 15-20 pts off the bench very often, so none of them are the "microwave" type bench player, but they don't need to be and aren't trying to be. Combined, they have gotten 12.2 pts/gm.
The one I am most disappointed with is Brissett. He could be filling a big role as a PF/Swing off the bench. I have not given up on him, it takes a while to integrate into a new team that is established like the Celtics are. But 17.6% FG% is just not going to cut it. I did a sort of players with >30 total minutes and Brissett has the worst FG% in the entire league of this subset. If he could get up to his career averages of about 40% FG and 34% 3FG, he would be right there with these other 3 main bench guys, getting regular minutes and helping the team.