I enjoy the Christmas period partly because I'm always on vacation during that time. If a winter break came into effect, I would propose post New Years and have a two week break.
For people who don't watch American sports, NBA always plays on Chritsmas Day and NFL usually has three games on Thanksgiving. The difference here is not every teams plays on those holidays.
I see people's point about playing through the holidays but I think two weeks off in January would work well.