Windows isn't just the shell.
If you want a custom shell - write your own, or pay for or join a community that is doing just that. It's perfectly expandable if that's what you're into, and there are entire communities and commercial products dedicated to doing this if that's what you want.
..and in the "old days" ... id agree with that
a much bigger change is needed now
<paste image - battleship turning - AGAIN>
edit - Customize - is not just a button
it is an ideal.