I can see the major point of making a microkernel is to allow kernel or other service (like driver) upgrade to be de-coupled; it would also allow much easier in

I can see the major point of making a microkernel is to allow kernel or other service (like driver) upgrade to be de-coupled; it would also allow much easier integration of non-open source driver and service, which could be a pain with Linux as it doesn't provide a clean way to do without rebasing (which could explain why Android upgrade is much lag behind for existing phone). But don't get me wrong, I totally support Linux philosophy.