This would not be in the Unix tradition. Traditionally,
/usr/include/sys already has all the kernel header files, or at least
a large part of it. Linux already deviates from this, as
/usr/include/sys is entirely controlled by the C library.
I'm not saying that one approach is better than the other, as I think
this is a matter of taste. What really matters is what happens when
user applications do include stuff of <linux/*.h>.
Regards,
Martin