There's this script, which essentially puts the information from the manual on-screen for you but otherwise works similarly to the built-in UI:
A more simple (but also more limited) UI where you don't have to type anything and just click buttons to adjust things could be made with a similar script. Or you could make some toolbar/menu buttons which do things like add/subtract 1 hour from different timestamps and use that as the UI.
Yes, the "Select Operation" box can be used for two of the three, but not for the Release date. It would have to be done one file at a time.
My idea wasn't to re-invent the wheel, more to zero in on what for myself and maybe others, is a subset of the numerous Metadata items. It's brilliant that you already have so much already available in the metadata panel.
Another way of looking at my suggestion is as more like a much smaller window into the metadata pane and extracting, using, only a subset, fewer items, for easier readability.
Basically as I said at the start, to have a Time shifting only user input GUI of some sort.
I would rarely make changes to the other items, but do occasionally have a need to change the Dates/times when cameras have not been initially set up properly.
Did you have a look at my dialog that Leo already linked? You select the files and enter a string how to shift your metadata dates as you mentioned in your original post (the screenshot of the docs).
its even an easier syntax than your example
and you could easily edit it according to your needs
Entering the string yourself seems easier to me than entering it into different boxes.
The SetAttr command allows only to shift one at a time so selecting several would need several runs.
I prefer the boxes, thats why I asked if something like that was available. You guys are very talented. Apologies for taking so long to get back, I got the notification, was very busy, then simply forgot till now.