The best place for feature requests is here:
https://github.com/modxcms/revolution/issues. If you post them in the Forum, they often slip through the cracks.
If I'm understanding you, you want the 'createdon' and 'editedon' fields of the resource displayed on the Create/Edit Resource panel and the Create/Edit Snippet, Plugin, Chunk, Template, and a bunch of other places.
For resources, you might take a look at NewsPublisher. It works in the front end only, but I think you could display those fields.
You could display those fields in the Manager with a plugin (especially if you want them read-only). Look at the ClassExtender code to see how to do it.
It's also possible that you could do it for Resources with Form Customization, but I don't think so.