I hate to say it but it seems like the crowds have increased since the economy took a dive a couple of years ago and everyone started doing 'staycations' closer to home at places like DLR, getting affordable APs, etc. It was always crazy crowded between Christmas and New Year's at DLR anyway, because it stands to reason that many folks are off work for that entire week, and they come to DLR armed with their holiday gift money or Hoppers/APs as gifts. So now, the overall increase in crowds has only made that week between Christmas and New Year's even more crowded than it was, I think.
But the real kicker is that it has now gotten crazy crowded even before Christmas. As I have said here on the DIS in the past, I was at DLR on the exact same weekend right before Christmas for 3 consecutive years - 2007, 2008 and 2009, and 2009 was, by far, the worst in terms of crowds. It was very daunting and really killed my mood to go into the shops I wanted to look in or take all the photos I wanted to take - or even ride some of the rides that my group and I love to ride a second or third time - because it was just TOO crowded to get around anywhere. For some reason, I could deal with the pre-Christmas crowds of 2007 and 2008. Yes, there were lots of people but it didn't seem as oppressive to me. 2009 was a whole different ballgame, however, and unless the economy takes a sudden turn for the better this year, and everyone decides to travel elsewhere for the holidays, I have a feleing it will be that way again.
So, perhaps, as DisneyMomma81 said, the best time to go and experience the holidays at DLR is early December. I suspect that once it gets to like mid-December, it will be a madhouse for the rest of the month.
At least you will have a few days at DLR in December, and you don't have to worry about squeezing everything into just one or two days, so you should be able to get everything done that you want to do - but just be mentally prepared for the crowds!!