I'm not a Bruins fan, but the proof is in the pudding with them. They led the NHL in points in 1990 for a reason. People say, "Well all they had was Bourque". Yeah so? It's Raymond freakin Bourque! The best defenseman in the NHL at that time without a mere doubt. Cam Neely was the best RW in the game outside of Brett Hull. Janney might have been soft but was scored at a 90 point clip in those days.
If the D is "mediocre" outside of Bourque and Wesley I still think you are in good shape. I wouldn't have called Don Sweeney mediocre though, just solid. Gary Galley? Not bad either. Plus the best goalie duo in the NHL. Moog was very capable of winning the Cup as a starter. Lemelin was a good back up.
Plus that team had a lot of character. Linseman, Carpenter, Propp, Poulin, B. Sweeney. Maybe these guys weren't 1st team all-stars but if guys like this are you're depth with Bourque and Neely at the top I think you're alright.