I think this is basically right. PowerShell is what you'd get if you started writing "the perfect shell" from scratch. But comparing to bash in isolation is sort of missing the point. Everything in unix is designed to work in the shell, and that's not true in windows.
So you have tools like ssh and nc and curl at hand, designed to feed each other via pipes and do one thing well. Want to push a file to a server behind a VPN when all I have is ssh access to a host on the network? Trivial. On windows? No clue. It's not a shell problem.
Copying files is an excellent issue: at some point I suggested either on the PowerShell blog or their feedback site that PowerShell should have the ability to copy files via remoting (essentially what you mention, you can remote into a box via powershell and need to copy a file from your local machine onto the remote box).
The response I got from someone at MS was quite telling, it went something like "please tell me more why you would ever want to do this, when we have existing folder sharing technology in windows". I gave up, if they seriously don't understand why that is NOT the answer to situation, gee...
So you have tools like ssh and nc and curl at hand, designed to feed each other via pipes and do one thing well. Want to push a file to a server behind a VPN when all I have is ssh access to a host on the network? Trivial. On windows? No clue. It's not a shell problem.