I think it is worth it at least once. We did it for just one day during the Christmas holidays last year. (Ok, actually I got two days in- one with my sister on New Years Day and the next day with my family.

) I have never seen it so crazy busy but I'm glad we tried it.
I'm not sure if it will be as busy that day as when we went, but it is still good to have a game plan in mind. If you do it, then this is what I suggest:
Get there early- this is not the day to sleep in. Even on those very busy days, the mornings were still very nice. The parks filled up sooner than usual but you can still get in some good ride time.
Know your priorities- Have a few must do rides picked out ahead of time. Don't imagine you will get on a lot of things. Anything above and beyond your priorities is just icing on the cake. For us, our main goal was to see HMH and IASWH. Of course we did get to do more than that, but not as much as normal.
Get FPs whenever you can because they will go fast. I believe it was around 1pm we got one more FP for HMH to return at 7pm.
When you need a break from the crowds, try Whitewater Snacks at GCH- just a short walk from DCA (great food!) or the Hungry Bear in DL. Food is not the best at HB, but we found it very uncrowded at dinner time and a nice place to sit.
I don't know how the days after NYE compare to the days right before Christmas but we have never seen it so crowded before and we always go in the summer. We didn't stay after our FP for HMH. We felt like we saw what we wanted to and it was just very crowded. I'm glad we went to see the all the decorations though. It will probably be a while before we go again at that time.