I think it's a good idea to be able to define Secrets not only on repo level, but also on Team and Organization level to avoid duplication between repositories.
This would be a tremendous improvement for us. We have many repositories under our org that we would like to switch to actions from travis. Having to specify half a dozen secrets on every repo would be painful.
This behavior is already available for issue and support template, as well as funding through org-wide `.github` repository like this one. I have started to work on a GitHub action to handle org-wide "labelling management" through a simple JSON definition but there is no org-wide events for now. So for the moment I will use GitHub API. Keep you in touch when I've got something stable.