We were there last week, and hearing your report, I am so thankful. The first few days were COLD - like 50 degrees that felt like 40. Winter parka weather, but better that than crazy crowds you are describing.
Good thing you have
MVMCP tickets. We did not and were disappointed in how non-Christmasy everything was. Just a little bit of non-eventful Christmas stuff around. Then one night, a wonderful CM at the Crystal Palace gave us some bracelets that allowed us to shop in the MK till 8pm on a party night after our discovery during that dinner that we had 82 snack credits to spend and the park was about closing, and the next day was our last one! Because of that, we accidently got to see the park during the party, and we realized Disney saved almost everything Christmas for the party. We had no idea how all those decorations instantly appeared without us even noticing, but the difference in the look and atmosphere of the park was night and day. It was astonishing almost. Standing on main street with the snow falling, the carols playing, the huge holly wreaths, the lights, the CMs dressed in Christmas attire, the characters in winter scarves really was one of the highlites of our trip. It was a wonderfully serendipitous moment all thanks to our crazy snack credit snafu! We all just stood there in amazement and pure joy, taking it all in for a good 20 minutes. It was bliss, and everything we hoped for in a Disney World at Christmas trip.
I felt so sorry for the people who go during Christmas and don't get party tickets because the trip alone breaks the bank. (It would have been almost another $1000 for our group to attend the party). Non-party goers don't really get to experience a real WDW at Christmas, and they don't even realize they are missing out!