We were there last week (12/4-12/8). Having only visited once previously during this time frame (re: 2008), I really can't compare to years past. The parks definitely were more crowded than we expected, but the wait times didn't seem directly in proportion to the crowds. We were able to do everything we wanted to do when we wanted to do it. For instance, we visited MK on Saturday night, entering the park about 5:30, and it was wall to wall people along Main Street and in the narrower areas (ex. entering Tomorrow Land by the Laugh Floor & navigating through Adventure Land). Yet, we still managed to ride the three mountains with FP+, scored FP- to Buzz & the Jingle Cruise, waited about 20 minutes for Haunted and the Speedway, and walked onto the People Mover, Stitch, & the Carousel of Progress. Ironically, the hardest challenge was finding a table at Cosmic Rays. All-in-all, it was a successful evening, especially when you consider we left right before Wishes (~9:45pm) because DD, who danced in the parade taping earlier in day, was pooped. And Saturday wasn't a fluke.
It was the same on Friday, yet DS & I hopped between all four parks and rode 17 rides including all of the majors, and on Sunday, yet we managed to do everything in DHS except for the shows (ex. L.M.A., Indiana Jones, etc.,) including two sessions in the Animation Studio, hopped to Epcot (rode TT [single rider], Journey into Imagination, Sum of All Thrills, S.E., & Soarin' [actual wait time = ~40 minutes] all without FP+or-), then hop back to DHS to visit Osborne Lights & hit our last traditional last ride - ToT during EMH.
So, while the crowds were indeed thick, the parks were manageable at least to us.