X.Org releases: present and future

Wouldn't you still have some churn post-KMS because modesetting support for non-Linux kernels would still have to sit in the driver?

(Or is the idea that new features implemented by the majority of devs who only really care about Linux will only get implemented in KMS, leaving users of other Unixes and older kernels out in the cold? I mean, sure, this isn't terribly important because the number of people upgrading X without upgrading the whole distro is measurable in hundreds and they can be assumed to know what they're doing, and the number of people running X on recent hardware on non-Linux systems is pretty low as well...)