Last year the decorations weren't as lavish as they had been in previous years. But, they are still beautiful. The hotel, itself, doesn't do anything special for Christmas Day. At least the didn't when we were there. They do have Christmas music playing
If you plan to go to MK do it very EARLY. It typically fills up quickly. We did it first thing in the morning and then left by about noon or 1pm. At that point they weren't letting people down main street anymore. They were having them walk behind main street to the back of the park.
On Christmas eve, though, they did have cookies and cider at the main entrance and were giving them out to guests. I don't recall them doing this any other time except Christmas Eve but I could be wrong. At the Grand Floridian, even before Christmas, they give out roasted chestnuts, I think.
Last year they didn't have the gingerbread houses at all the resorts. They did have them at many of the deluxe resorts. And, it is definitely worth seeing. Make a special trip to the Grand Floridian as their decorations are the best. They have a "full size" gingerbread house that is a gift shop that the staff made. It is truly amazing. And the tree...wow!
Anytime after Thanksgiving is Christmas at WDW. It is the best time of the year to go. Everything is so festive. Don't forget to see Osborne Lights at MGM. Nothing else like it. And the lighted arches and Candlelight Processional at Epcot.