You focus an awful lot on what Moore has over Del Zotto (a couple of months of age? Really? You are reaching here). Yet you conveniently ignore the biggest difference between them. Production. Del Zotto generally scores more in a year than Moore has scored in his career. MDZ had proven, in three different seasons, that he can be a point-producing D in this league. He's gotten Norris votes in the past. Has Moore ever even won the Broadway Hat?
Again, I think the issues are primarily twofold. First, MDZ can't play on the right. His skating issues, which aren't that noticeable on the left, are magnified on the right. Second, MDZ (and Moore, and Girardi, and ESPECIALLY Staal) seems to have a bit of trouble with the man to man defense that AV loves. Before dismantling a top group of defensemen for peanuts, I think it would make more sense to try implementing a zone again. I won't argue that DZ isn't struggling. He is. That's not my point. My point is that every other defenseman (except for McD and to a lesser extent Stralman) is struggling just as much (Girardi) or even more (Staal and Moore) than MDZ. The magnifying glass is on MDZ right now because AV loves Moore for some reason, but the second MDZ is gone, you can be sure that the other guys on this list will start getting the same treatment.
This team really has ONE thing going for it--defense. Some of you are just too quick to give that away in my opinion (particularly when we struggle to score and, when used properly, DZ is our best offensive threat from the back).