I would just let them know that you have different plans for next year. How hard can this be?

You could suggest an extended family vacation for next winter - something where everyone gets their own hotel room/cabin/beach house but spends some time together. Maybe your parents could spend an afternoon with the kids while you and your spouse relax. . . Sounds perfect to me! Any family members who don't want to do the family thing will just stay home.

You need to plant the seed a year in advance.

Well, in these circumstances I think I would simply make plans with DH for yourselves and your kids and let everyone know you're doing something different. I suspect many people don't really enjoy large, obligatory family gatherings on holidays, but it's often obvious. The expectations associated with holidays can make everyone feel stressed.

There's rarely if ever an outburst, but the extended family gatherings have become just something everyone has to do rather than looks forward to. It's obvious. DS's siblings obviously are just going through the motions, FIL is half out of it, MIL is indifferent. My own parents and siblings are there because they want to see the kids mainly. DS and I would love to break out eventually and take the kids on vacation for the holidays (skiing or maybe a warm climate). We'd catch up with the families probably separately later on for the obligatory gift exchanges. But how do you do it without ticking off everyone in the process? Anyone in the same boat?