I love OKW and have visited many times, several in December, but in all honesty it is one of the least Christmasy resorts. They do decorate and it is festive, but if you are looking for serious Christmas spirit it is not the best choice.
I would recommend Wilderness Lodge. The Western theme really fits the season. The decorations are spectacular and the massive fireplace in the lobby really enhances the mood.
Another good choice is the Grand Floridian. All the resorts will have a gingerbread sculpture in the lobby, but the GF will have a house big enough to walk in.
Good luck and have fun.