Dan Boyle has played on some crappy teams? Are you referring to his early days in Florida, which are completely irreleant? In his 5 full seasons with Tampa Bay, he was a part of 2 Division Champions, was in the playoffs 4 times, and won a Stanley Cup. Boyle is now in his third season with the Sharks. The Sharks averaged 115 points, 52 wins, and were the #1 seed in the West in both of his first two seasons. Nothing too different about this year, either. He is easily the second-most important player on the team behind Joe Thornton, and honestly, if you ask your average Sharks fan, they will tell you that there is a better chance of winning without Thornton than without Boyle. He plays incredibly heavy minutes against the top forwards of opposing teams, and he has shown an ability to frustrate certain star forwards with his play. Alex Ovechkin comes to mind. Boyle was a key defenseman on a Stanley Cup champion and had 14 points in 15 playoff games for the Sharks' last year. If you watched the Olympics, you know what he brings to the table in big games.
Boyle is a far, far superior defenseman than either Tomas Kaberle or Bryan McCabe. Is he a Hall of Famer? No, of course not. Barring an incredible close to his career, of course. But to illustrate how much better he is than Kaberle and McCabe, let's just say that if they are probables, Boyle is a lock. As it happens, neither of those claims are true. But with two Second Team All-Star berths, three top six Norris finishes in the past 4 years, and playing 26 minutes a night for one of the best teams in the league, Boyle has long passed the Kaberle/McCabe threshold. Those two defenseman have combined for a grand total of one top ten finish in Norris voting, 0 postseason All-Star teams, minute playoff success, and are far less effective defensemen at ES than they are on the PP.