Good thought put into this, nice start 
My thinking comes from a belief users may need an advocate or ombudsman if they have been unfairly treated by a moderator.
If there existed a mechanism for moderation reports like you’ve suggested or like law enforcement does with each arrest it may held assure people are treated fairly and with respect.
Place yourself in a situation where you believe you’ve been treated unfair and the moderator is it, they are the big boss, you have no one to go to and explain that the punishment doesn’t fit the crime.
So data explorer could , staff action logs, seems the mechanics may already exist people just need to understand the idea is to allow public viewing, public enforcement, why has a user been locked at TL1 for three years?
Ohh, we can look at the report right here on their public profile, they’ve had these actions taken against them, they all look reasonably fair too, nothing to see move along.
Or, in the same situation that user has been locked unfairly as a moderator enjoys their authority to much, time to now flag the moderator.
This suggestion does not arise out of nowhere, there’s a need, question is does anyone care if they’re not the ones being treated unfairly?