My NYE experience a while back:
They started passing out horns in Epcot literally around 4 PM. So the park was JAM PACKED, and almost everyone started blowing the horns nonstop. I don't want to tell you how to live your life, but chances are you might have a similar opinion : a crammed park sucks. A crammed park filled with thousands of people blowing horns for hours sucks more than the human brain is able to comprehend.
At about 7-8, my wife and I realized it was either leave the park, or have our trip ruined by the inevitable trial for our murdering another person.
We went over to Downtown. This is the perfect medium. You get a good sized crowd - more than you'd like on a random day, but a nice large crowd to make you feel part of a NYE celebration. The Downtown stage has stuff set up for NYE fun, if you like that stuff. But most importantly, there's an official countdown.*
Where you want to be at midnight is fully up to you, obviously. But being at Downtown with your SO - I can fully recommend that as a wonderful balance of fun crowds but lacking the "I wonder if the plastic fork I got from that food stand could kill multiple people" aspect.
*Regarding the countdown. My girlfriend (now wife) were mulling around with a handful of people. One person said, "Huh. It's 5 seconds before midnight." Sure enough, it was. So we all looked around and let out a confused, "Uh... yay?" And did some half-hearted kissing. We thought NYE was kind of ruined. A few minutes later, the stage got the "Official Disney" countdown going. So we got to be part of the big celebration, despite the fact that Disney didn't give a fug - they celebrated midnight on their own terms. So at 12:03 we got to be part of the "ball drop". My gf and I didn't care - as far as we were concerned we got to be part of two "midnights", one small and one big.