Called it!!! Looks great! I would've been so disappointed if they didn't do anything!
Hopefully this is only the start and that eventually this will be the first USH ride to do a full Holiday overlay and they do a special ride film where Gru (as Santa) and the Minions (as Santa's elves) try to save Christmas for the girls, and wacky holiday mayhem ensues! Seems like a ridiculously natural fit!
(Hell, if they wanted to go the cheap route and not do a full new ride film, they could basically do a literal overlay of the current ride film, which already involves a present. Just add more holiday decorations and gags throughout the ride and queue and change wording from "adoption anniversary" to Christmas)
But of course I'd rather they do a full new ride film! It would pay for itself. It's Universal's biggest property, would offer a holiday overlay for a ride in the park, and they could reuse it year after year. It would essentially be a new ride vehicle program, film, and decorations. Even more simple than the overlays that Disney does, since after Universal does it one time, it'll just be saved as a new ride program in the computer.
I mean, gosh, they have a Minion Rush Holiday Lab version of the Minion game!!! There's so many possibilities with this franchise.
I can already imagine how they can further decorate SSFL. The two blue cone "hills" can get a star on top to be Christmas Trees! Etc.