We will miss Barrie at times this year. Not the whole time, but there will be stretches where some will yearn for the consistent blue line scoring that he provided.
Barrie was never as bad defensively as his worst detractors portrayed, but he was below average for a top pairing guy, and he had moments of pure uselessness. But the scoring usually made up for it.
The total.scoring from the back end will be down this year. Byram is unlikely to make a significant impact this year, if he even sticks. Makar will not hit 60 points, though 40+ is my prediction. Girard may help fill in some of that gap, but EJ and Cole will be lucky to match last year. One of the new PMD guys replacing Nemeth would help, but then you are giving up some of the defensive ability that Makar might provide over what Barrie did. Last year, we got 166 points from the blue line. Next year, we are looking at Makar 40, Girard 30, Zads 15, EJ 25, Cole 10, Rosen/Graves/Timmins/Connauton/etc 35 combined, for a total of 155. And that is an optimistic total, expecting 35 points from the 6D spot.
The team as a whole should be able to score as much or more given the changes up front though. And 2 or 3 years down the line, the D will not be missing Barrie at all. But there will be times this year that having that veteran rover will be missed.