The NHLPA apparently refused to agree to the league's realignment plans, which has led to the league postponing the revamped schedules and formats until at least 2013-14.
Here's the link to the nhl.com story. Deputy Commish Bill Daly sounds pissed in his comments. I think the proposed realignment will happen; it makes too much sense not to. But reading between the lines, I think the players' union has decided to make realignment a bargaining chip in the upcoming CBA; they'll want to get something in exchange for their "concession" on the issue.
Would love to be wrong here. Time will tell.