I guess the problem is the age old battle of facility versus abuse. I remember a book on security that specified a secure computer as one with no networking, no ports and in a secure room. Even a keyboard was questionable. Not very useful though.

The problem often appears to be user ignorance (they don't know) or arrogance (they should know better). I have had to recover a family member's computer because they couldn't help themselves but open an attachment because it was so tempting. They knew better. Similar experiences with FaceBook apps too.

PowerShell is too useful and central to remove, however, there is nothing wrong with leaving it locked down. If necessary require changing the execution policy each time a script is run to avoid remote access and privileges.