It seems like the scheduling change may have something more to do with their opponents than it does the Blackhawks. Their game on 12/13 against the Capitals is now on ESPN, while their game on 12/23 against the Blue Jackets is no longer on ESPN.
Washington isn't a lot better, but they are definitely better than the Blue Jackets, so you have to assume the NHL is expecting a better matchup between the Capitals and Blackhawks.