I haven't missed bringing in the New Year in WDW for 5 years now. Nothing beats watching the Illuminations show and the added fireworks for the New Year.
The crowds are crazy, but I don't go to WDW during that time of the year to ride the rides. I enjoy the shows, expecially the Candelight procession. The little talks by each Santa of each land, I love learning the history behind the Santas. The different entertainment each country has throughout the day. All the extras I miss on "do the rides and shows" trips.
I also take more photos during my NY trip than I ever take the rest of the year. But I never come home with photos. Last New Years eve before the rains (torrents) came I took over 100 photos of people I didn't know. I offered to everyone I saw to take their entire family photo. Everyone loves having a group photo once in a while instead of always leaving out either mom or dad.
I don't go to the MK on NY eve, Epcot is my park for the night, but others love the MK best. Maybe if they take Illuminations away I might make the hike to the MK for the NY, but I dread that day, I could never live without Illuminations. Peggie