Have they changed the article since this afternoon? The link you posted says that the defense isn't set yet.
As for Del Zotto, I am completely baffled by how they are handling the situation with him. You are correct. Del Zotto does have a longer track record in this league, and that track record shows that, when used properly (ie- in the right system and on the left side), Michael Del Zotto can be a regular 35-40 point defenseman. We haven't had many of those in the last ten years (and it ain't from lack of trying).
People have tried to claim that the fall-off started last year. It didn't. For the first half of last season, Del Zotto was our best defenseman (period--he was even better than McD at the start of the year right out of the lockout). Then he picked up a hernia.
A player doesn't go from developing star D to trash in one off-season. I don't know what it is, but there are plenty of possibilities. It could be a confidence issue (repeated scratchings when worse players have been dressed, trashed by coach in the media, CONSTANT trade rumors). It could be playing on his off side (which has exacerbated an issue I've had with how they have developed MDZ from the start. Almost every other D, you can give a name or two for their regular partner. McD and Girardi. Staal and Stral. Staal and Girardi. Now try and figure out MDZ. He's had about a dozen partners since he came into the league, and I think the most consistent was Sauer, who was with him for about 20% of a season). It could be lingering issues with his hernia surgery (I don't think so, but hey, every time Cally and Nash suck, this board assumes they are hurt, even when they state otherwise). It could just be a down year--they happen.
If I had to hazard a guess, I would say that the biggest two issues have been playing his off side (he isn't a good enough skater to adjust quickly enough over on the right. It's why he has so much trouble keeping the puck in the zone on the right) and the new man to man defense. If the latter IS an issue, I don't understand why AV doesn't just adjust his system to suit his new players. MDZ, Staal and Girardi have all thrived while playing zone D and they look significantly worse in the new system (particularly Staal). McD looks better in the new system, and Stralman has generally looked better as well (though he was struggling a bit the last few games before he got hurt), but they (particularly McD) also did quite well in the zone.
It just seems like idiotic asset management to move a guy (who, just a year and a half ago, was getting Norris votes) for peanuts. Why not try going back to Zone D? 3/4's of our top 5 defense played much better in that system (not calling for a full return to Torts hockey--just the zone D).