I agree with Tink.
I would say this.......to really enjoy Epcot on NYE, stay away from the park until that night. Rides are nearly impossible to ride without super long waits, and the crowds are heavy all day.
During the day, find a place outside the world to go and have fun, or just relax.
We went in at 9:30 pm (and Soarin was a 2 1/2 hour wait even at that point).
I agree about the way it gets a little more crazy the later it gets. I personally am not a drinker, partier or anything. Im 26 years old and married (no kids). Im the family-man type. I just like being with my wife and enjoying the time together. With that said, the NYE crowd sort of makes me uneasy. I just feel that people are not themselves during that time. I dont like the looks people give and as a male, it seems that men without any respect for other people, seem uncaring of the fact that my wife is married with her husband standing right by her. I dont deal well with that as it makes my wife very upset.
It's just sad that people don't know how to drink like adults.
With that said, Epcot is not that bad, though we did see some acting a little overboard. Overall it's pretty tame and I think it's the best place to be on NYE.
Again, show up later in the evening and leave late. Also the park is generally open until 1 or 2, and most everyone leaves right after the fireworks at midnight, so if you stay afterwards you can ride about anything you want with little to no wait.