I seem to recall Josh saying something about not posting recommendations for those weeks because people just attack him that he's wrong when basically every park is INSANE. A few thoughts:
#1 - wherever you go be there 30 minutes OR MORE prior to park opening.
#2 - If you want to take advantage of EMH then consider a park hopper
#3 - consider taking a break in the afternoon. The park will be at their busiest from 11-5.
Here is last years calendar which may help:
http://www.easywdw.com/news/december-2014-disney-world-preliminary-crowd-calendar/