Too much in the kernel already
I wish dists would stop heading off down the MS route and throw everything into the kernel that seems like a cool idea at the time. The kernel should be lean and mean. If you want KVM fine, have it as a loadable module. But do not integrate it completely into the kernel - it'll just be more bloat and more to go wrong.
Why distributions can't just stick to the stock kernel anyway beats me - its Unix in the 1980s all over again. The added value should be in the extras they provide in their distributions - they shouldn't mess around with the core software.