OK, I will respond to this one. I have been to Disney on NYE. We went to MK during the day and then switched over to EPCOT. When we at MK is was very crowded and they were saying that the park was full. Now when we were leaving there were 2 or 3 boats full of people coming across the lake. We didn't understand how it was full, but more were coming. If you really have to see the fireworks, I suggest you get there in the morning. It seems like resort guest can still get in, but not others. That was my take on it anyway.
As for the drunks, at MK they do not sell anything to get you drunk so I am not sure how they did that. We did not have any trouble, but it was early in the day. Now at EPCOT there was always a very long line to get beer. I mean a very long line. Now we were there and we were drinking so this might be a little bias, but I can only remember one drunk person. At least only one who stood out. Everyone was having a good time, but drunk I don't think so. There was a lot of drinking and it is very crowded so people might think everyone was drunk, but personnally it was just everyone having fun. It was not like people were falling all over each other or anything. I think the biggest problem is that there are just so many people it makes other uncomfortable. I hope this helps.