There are some conflicting things, why would you do a clean OS design(this would be great and i would very much like to see some experiment with serious effort)

There are some conflicting things, why would you do a clean OS design(this would be great and i would very much like to see some experiment with serious effort) and write it in C? You would already be throwing most of useful programs that exist today. If you no longer write it in C why would you need to parse C headers for calling "foreign" code? The point on software not taking enough advantage of hardware is on point. I would also like the hardwares(e.g. SSDs) to expose a bit more how they work rather than have another CPU emulating spinning disks.