Is this an idea, or a question?

I don't know of anything automated.. this is generally something that you would have in your documentation about how events are being used, where they are being used and what dimensions can be correlated.

You could probably use something like a list variable (Hit expiry) and code some solution to list all dimensions in use on every call...

Then you can create a table that if you add any metric at the top, and use the list var as your breakdown you can see every dimension that has ever been used with that event....

You would have to do a little JS code to determine which dimensions are in use on your calls, that shouldn't be too hard.....