There are standards. There just not called POSIX. For example the filesystem hierarchy standard.
Which by the way, is fully-documented here:
http://www.pathname.com/fhs/
Yeah, my example wasn't the greatest. I'd have said SUSv03, but I didn't think as many people would be familiar. Also, my desire for POSIX extends beyond command line to basic programming APIs. The deficiency of Windows just seems most readily apparent on the command line.
It sounds like what you really mean is that you want Windows to be more like the other Unix-like systems you use. There's no standard for that.