Why this is a great time to go to Disney...

1. If you aren't a crowd person then this is the time to go to Walt Disney World. I have relative that head to WDW during this time of year for the crowds are very small. This way you won't be standing in line to your favorite attractions as long. I have gone to Disney World myself during the off season and enjoyed going onto Splash Mountain and only having to wait 30 minutes. When you go during the mid to high you can be waiting up to two hours or longer to get on that attraction. Plus going during this time means you don't have to rush to get good seats at the shows, you can arrive within 20 minutes and still get a good seat. I love this time of year and like that I don't have to wait for my favorite attractions. Once friends of mine and I got to ride Tower of Terror five times in a row without having to wait more then 10 minutes!! So, if you enjoy small crowds then this is the time to head to WDW.
2. If you don't like 90 degree weather, where when you walk outside your resort room and can feel the sweat already rolling down your back, then this is a great time to go. The nights are normally 35 to 40 degrees and the daytime is 50 to 65 degrees. I come from up north so this weather is my favorite, since it's about -10 degrees here at night and gets to 15 degrees during the day. I love being comfortable walking around the parks and not dying of thirty or always hunting for shade. 
3. Can get into the places you want without much fuss. Since not many are visiting Disney during this time, it's more likely that you will get into a restaurant you want with even making a last minute reservation. If there are some wonderful restaurants that you have always wanted to eat at and couldn't get into, then try going during this time of year and you might be surprised at where you get into:)

Starting in January to mid February is when Disney is pretty quite. You will enjoy Disney and finding that you are much more relaxed and maybe even slowing you pace as you walk through the parks.