As far as I can tell from reading various metadata sites, no one uses all the metadata fields. Even in my own use, I have found situations where I've used different fields.
With the advent of the the ITPC extensions, and the PLUS system, I can see the meta data going on for a 3-4 screen scroll bar.
Some metadata you apply in a batch, and don't ened to look at. E.g. your personal copyright notice, your contact info.
Some metadata you apply as a batch, but you may want to verify
Some fields you really never use.
I would like to be able to prune the fields that display when I click the blue i button.
I would like to have possibly several preset field templates.
I see this being done in a panel similar to the the stationery, where you apply checkmarks to fields you want to see on your entry form. You can save it as a preset form.
Example: when I'm working with output from my camera, capture date and image date and digitization date should be the same. When I'm working with scans. digitization is a much later date (about 30 years) than image date. In the first case, I don't want to see digitization date.. In the second case I want the date to be set to the create time of the image.
And I never use model releases.