It would be nice to be able to create test/demo users with different roles so we could see what they see and try out different functions on them without the risk of it affecting live data. They would have full functionality of their role but be marked in such a way that whatever happened to them would only be demo and excluded from anything live.
And a demo mode, such that pulls from everything live but that does not affect anything live. It would be nice to be able to test the cause and effect of actions and processes and make sure things work they way we envision them working.