Ability to determine what reports custom attributes and metrics are included in

I find it very difficult to manage custom attributes and/or metrics. I would love to determine what custom work is being used on which reports so I know:

1) Is it safe to delete it? 

2) If I edit it what reports will be effected.

Having a page listing all custom attributes and metrics with a list of reports they being used on would great benefit the task of cleaning up unused custom work.