TL;DR; (“too long; didn’t read”)
There are some people who don´t have the time to read the whole text – if you are familiar with the topic the text in bold includes the most important points and is just for you.
The most important points to enforce Powershell Security is to use the newest Versions (OS and Powershell), use whitelisting and enforcing the usage of the ConstrainedLanguageMode and establish a good rights structure with frequent centralized logging and validate all the new features coming with the new Windows 10 Versions. And now in more detail:
Power in the shell 