Perk has improved every single year in the league, first by remaking his body in his first few years, and lately by learning how to be effective. The jump he made on the defensive end this past season was remarkable, to where he's considered one of the best defensive centers int he entire league. He can do both things one needs to be a good defensive center - guard the post and hedge and recover on the pick/roll on the perimeter. His protection of the rim, through shot blocking and hard fouls, is also very helpful.
I expect Perk to get a bit more respect from the refs in the future, which should help him continue to keep his fouls down. On the offensive end, e just set the single season Celtics FG% record. I don't see him as a volume scorer ever, but as long as they dump the ball to him a couple of times a half, his scoring should uptick a bit as he matures.
It really doesn't matter if Perk puts up a 6/6 or an 8/8 this season, because the Cs can win with him just doing what he did this past season. Stats don't tell the story of this guy's value to the team, and probably will never define him. He's a unique player in that his best attributes- backboning a great defense, setting picks and throwing his big body around, making outlet passes, and defending the rim, don't show up in the stat books.
As a basketball purist, I love Perk. He's shown a ton of character ever since putting on the green jersey, first by working his butt off to get on the court, and then by putting out great effort and really caring about the team while they went through tough times. This past year, when the Cs needed him the most, against the Pistons, he stepped up big time. In my opinion, anyone who can't appreciate what this guy brings to this team doesn't truly understand team sports. Any guy who shows the willingness to throw his body around every single game, without the need for individual glory, gets my respect and gratitude. And Perk has done that on a 66 win championship team, as well as a 24 win team.
Unfortunately, we can't have $15m+ players at every position. The still 23 year old Perkins will never be a volume scorer, but that's OK with me. Just keep doing what you do, big guy, and improve a bit every year.