This is not far from how most of Sweden operates. Most offices comply to the idea of "half-day before holiday" notion and as where fixing the dates wouldn't interfere with that too much, I doo believe that fixing Christmas to a Saturday would make a lot of Swedes angry.
For one, we celebrate the 24th, and having the 25th on a Saturday sure gives Friday and half of Thursday off. But the 26th is also a holiday, which would then be on a regular Sunday. New Years Eve is not a holiday, and having that on a constant Friday would open the days between Christmas and NYE as a work week. Where as now some years you can have a nice long (10-14 days) vacation with only a couple days of actual leave, because the rest are considered national holidays. (Example: 2012 I can get 14 days off with only 5 days of leave.)