I completely disagree, the whole concept of a bad 3rd pairing being ok, doesn't really exist in the modern NHL teams have identified that as a key area to create gaps on lesser teams and strongly contribute to carrying less talented 3rd/4th line players to above average results.
The exceptions to that are the once in a blue moon 2 HOF d-man who play the same side for 25+ mins a night like Pronger and S. Niedermayer. What we have on our right side is Bouchard who played a career high 23 mins last season and then if J. Brown is playing 15 mins that means Emberson or Stecher is playing 22-ish mins!? Yuck! It's also worse cause Bouchard is an OFD who you clearly want to deploy in offensive situations which means less defensive zone draws which puts our suspect RHD in tougher situations more often.
Last season:
Desharnais in 78 games: 1g 10a +3 playing 15:44 per game on one of the best teams in the league
Brown in 51 games: 3G 7a +2 playing 14:45 per game on one of the worst teams in the league.
Brown needs to cover about one extra shift per game to make up for the loss of Desharnais.
They’re both bottom pair do nothing plugs. They aren’t difference makers either way. Browns been a bottom pair plug for nearly 300 games in the league. Kulak will be good enough to cover him just like he was good enough to cover Desharnais.
Emberson is the big question on whether he can repeat his 30 games from last season with an expanded role and expectations.
I think the make or break cog on D will be Nurse. If he plays like last season that entire 2nd pair could crater given Emberson has a mere 30 games under his belt.
22 minutes a night, a plus player and 30+ points isn’t going to crater your 2nd pair.
Nurse is far from good value on his contract, but he’s not going to crater your second pair on his own.