If you will also be there on Dec. 30, then maybe you could do both. The times we have been there for NYE, MK has special fireworks on BOTH Dec. 30 and 31, so you could do MK on Dec. 30 and Epcot for NYE.
Right, if I were at BLT for Dec. 30th, I would head up to the TOWL to see the fireworks from there out of the crowds!
We're not staying at BLT, but will be at MK for the 30th. We've been there for the last 3 December 30th. We have found that most people stay even after the fireworks, so getting back to the BWV has not been a bad hasstle, and the one time I remember the time, we were back in our BWV by 12:40AM! Last year it was the most crowded, but still we got back to BWV at a reasonable time.
On the previous 3 NYE's we've done Epcot. The first time we didn't know better and stayed at Epcot from 5PM on. We had a 6PM ADR, and when we used the restrooms at the restaurant, we didn't realize that was the last time it would be easy. The crowds were crazy! At 8:30 or so, Epcot showed Illuminations "for people with children" and I think people did leave after that, but then the crowds really streamed in. DH and I watched the movies, Canada, France and China, 1-2 times each, sort of found a place to stay and did enjoy the fireworks that began around 11:40 with smaller celebrations of fireworks lit from each of the countries.
The next year, we didn't bother to enter Epcot until 11:15 or so, we spent the time enjoying the boardwalk activities. There was no problem getting into the International Gateway at that time, we walked over to the bridge, and watched from essentially the same place that we had the year before.
Last year we joined a group for an Illuminations cruise on NYE. It cost $100 pp, but worth it IMO!
This year, we're going to see the fireworks at DHS, so something we have no experience with. We have a fantasmic package, we'll go to the Osborne lights, we'll find a place and hope for the best. DS and one DGD went to DHS our second year and they had no trouble entering that park around 5....we'll see how this works out.
Because lots of people with children do leave after the first set of fireworks, I do think you have a chance to enter Epcot at a later time than many people mention. That has been my experience. We had listened to people our first year and have gone our way since then. Best wishes, enjoy the fireworks!!! I do, and that's why WDW is my choice of places to be on NYE!
Bobbi
We are a blanket family, I carry one/two small fleece blankets in and they just check it during bag check, let us in. I have used them for cushioning to sit on a curb during Wishes throughout our stays. 
