Hi there!
I might be going this winter, as well, but nothing is finalized.
At EPCOT, Soarin' just got a new movie. It's the same (or mostly the same) music, I'm told, but you'll have to see it yourself to find out.
Frozen Ever After also opened recently, located at EPCOT in World Showcase where Maelstrom used to be.
There's a new nighttime show at Hollywood Studios that's Star Wars themed.
When exactly are you going? Mid-November through December Magic Kingdom has Mickey's Very Merry Christmas Party running, which is a separately ticketed event. All through December the other parks and Disney Springs have Christmas decorations and events going on, as well.
That's a ll I can think of for now, but I hope you have a magical stay!