Earlier quoted context omitted.
Powershell ISE
The ISE is clever, but honestly, nothing beats a PuTTY-like terminal.
I do agree with the core of your point though; an actual terminal with actual commands that actually work well would be great.
Windows Powershell is actually really fascinating from one point of view though: the idea that instead of passing raw (inconsistently formatted) ASCII/Unicode data between pipes, the data is actually presented in terms of a data structure; thus you can easily say 'sort by the third column descending' or 'show every second record'. A significant amount of my bash scripting on-the-fly tends to be chaining several commands together to munge output data solely for the purpose of letting the next command parse it properly. Powershell, in some ways, takes care of this.