This was us two years ago. We have gone to Disney for Thanksgiving every two years since 1997, when my parents decided to buy DVC. I have three younger siblings, and two of them, along with myself now have our own kids, so scheduling has gotten harder.
When DD (now 10) was in 1st grade, we took her out for the week following Thanksgiving because I just couldn't give up that trip. It was fine. The next time, she was in 3rd, and that was harder, so we took her out for 2 days before (they have a half day the Wednesday before Thanksgiving), and 2 days after.... That was rougher, and I caught some flak from the teacher (which I understand, and feel guilty about, but this is my favorite time with my kids). Next year she will be in 5th grade (and my little one with be in 1st grade)... and I am going to take them out for 2 days before, and 1 day after (See, I'm getting better each time

). Heaven knows what I will do once she is in middle school. My in-laws already think I am a horrible parent for taking my children out of SCHOOL, to go to DISNEY - which they see as a complete waste of money (they live in Florida, and we can't even get them to join us for more than an afternoon there!).
But this year we have an added dilemma. I just found out that my brother and his family (1st grader and 2 year old) won't be coming for the Thanksgiving trip, nor will my sister (no kids). There will still be 10 of us (other brother and their two little ones, and my parents), but it will feel so weird. My mom and I were talking about it, and we are going to have to find another time of year to do the whole family.... but it makes me sad.

I love Disney at Thanksgiving. We always stay until the Monday after just so that we can do
MVMCP.
So I definitely feel your pain. I am guessing that will all my nieces and nephews spread all over the country (Northeast, Pacific Northwest, California), and everyone having different school breaks, the only time we are going to be able to organize is summer.

I am sure I will find things to like about summer at Disney too, I am just going to miss our annual tradition.