Of course, these things don't happen in a vacuum either. Say Gryz plays top pair...what happens to the 2nd pair or especially the 3rd pair?
Subtract Chara's 21 and Torey's 20, replace with Gryz and someone else. Bottom pair replace Gryz with someone someone else and you've arrived at more questions than answers.
All good points and you do have questions to answer- part of me just feels like it is time to see what the younger D men have in terms of game. I do think there is an argument to be made about the point I quoted above and that is the traditional view of pairings. Carlo and someone really defensively solid - Lauzon, for example, if he can take that next step, should be your top defensive pairing, going against the top lines most frequently, and D zone starts when Top 6 guys are out. A Mac/Gryz is a top pairing for o-zone starts, second and third lines and faster more skilled opponents. You can balance out minutes through matchups and not get Gryz overwhelmed in the cases where he might have to tackle a skilled 6.2 220 lb guy.
It seems to be me a good solution if you are willing to take a bit of a chance (and really any new signing/promotion is taking a chance: that the player stays healthy, gels with his linemates, sustains a level of performance, adapts to a new play style or system, gets along with the coaches etc). That defense might not be as good overall (it might, though) but it is good enough that the team is not going to go into the toilet and give up four or five goals a night. If the needs still exists 40 games in, make a trade, or do something at the deadline.
Of course it is a total disaster . . .