Having been spoon fed Mitchell bailing out Bieksa and Salo Edler, could it be that defensively there are dmen who hold their own (some more some less) and those who can do more?
I feel that Garrison, Bieksa and Edler can hold their own (Garry more, Edler less) but can't help their partner much - due to a combo of lack of footspeed, mobility and anticipation). You can even see this in the way they defend.
Whereas Hamhuis and Tanev can do more than hold their own. So pairing them together is not optimal unless the opponent has only 1 scoring line because it weakens the 2nd pairing. It has also turned an offensive dman who can rush, pass and shoot into one afraid to make mistakes defensively (of course, being yelled at by the coach doesn't help).
Edler - Tanev
Hamhuis - Bieksa
Stanton - Garrison
should be more functional - more offense, better 2nd pairing defence.