I disagree. I think much of the weaknesses of Windows - especially its security woes - are due to trying to be too backward compatible with previous versions, which has meant that long standing problems have either not been addressed, or only inadequately patched over.

Making a clean break with the past and moving to a new system where network security is fundamentally designed into the product from the very beginning, even if it's not based on a Unix clone, would be move in the right direction.