I think this plugin is a great move in the right direction! It's like when you need to let the mechanic take a look under the hood of your car, but as an end-user, you don't always want to see the engine to enjoy the ride.

It makes great sense to start providing a debugging library layer for the Gutenberg project and support developers with different access levels.

I doubt it will be of much help for the end-user to manage complex layouts. Complexity is not reduced through more complexity, and this experience should be embedded in the core of the layout system (blocks), not as an afterthought.

I hope that more people will notice and appreciate this plugin's goal and limit its purpose before going overboard with new fancy features.