Our family is here now and did animal kingdom on thanksgiving. The crowds were very manageable. In fact its the 2nd time we have visited AK on t-day. Both times had moderate crowds. Wed was crowded at epcot and friday was very crowded at the studios.
We did Animal Kingdom on Thanksgiving as well and experienced what you did. We did Epcot on Friday and did what we wanted and it wasn't that crowded either. Saturday was the Studios where we did most of the things there. Sunday was Magic Kingdom and that was pretty good too.
I think we just either lucked out with the crowds or I know how a Disney World guest thinks and just do the opposite because I never looked at a crowd calendar, I had no idea of extra magic hours or when Mickey's Very Merry Christmas Party was, and I really didn't know the park hours. We totally winged everything and had a fantastic time.
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I think if you return to WDW, checking on the best parks/worst parks for each day would help a lot. And there is no need to wait 70 minutes for E:E. do it early or FP.