Three years in a row, we've been in the MK first thing in the morning on Xmas Day - seriously, we are early birds and have been in the park no later than 7:30 on any of those mornings. If you're early birds and happy to get in at the crack of dawn to do a lot of rides before 1, then enjoy things like a sit-down lunch, the Hall of the Presidents, the Carousel of Progress and a few of the other relatively-short-line things - and your three fastpass+ choices - or Park Hop to another park, or head for a movie or a DTD (Disney Springs?) reservation, then you'll have an amazing day. We love the excitement, and like you, we aren't there to try and clock in 20+ rides in the day. If you're able to plan it 180 days out, you should be able to do Christmas Night dinner at Be Our Guest - or head out of the park like we did last year for a late dinner at Cali Grill that lasts until the fireworks show.
And yes, we are doing it again this year, but not on Xmas Day because of schedule conflicts - we will be there most of the week thereafter.