I have yet to find anything from Microsoft that states the kernel for Windows 8 has been rewritten. As I look at the kernel modules, I see a lot of commonality with Windows 7 and its predecessors. I see new API's, and old API's. I see the memory management has not changed from Windows 7 64 bit either.
Mind sharing a Microsoft link where they state it is a rewrite? I cannot find one and I would like to read about it. I see a lot of guesses about it on the Internet, but nothing from Microsoft.
Regardless, there is also nothing that states a rewrite would be of any benefit anyway. It is just your opinion that it is better, which flies in the face of facts. It is still buggier than Windows 7 and that is a fact.
By the way, Windows XP is not my "pet toy". Microsoft created it. I, and a few million others, used it. My home computer is running Windows 7, and my work computer is getting ready to run Windows 7. I go with what does the job the best. Right now, that is Windows 7.