I'm sorry this has taken so long, but we are working on some foundational API's to manage and list images right now: https://gitlab.com/gitlab-org/gitlab-ce/issues/55978. I've also added your feedback on sorting, thank you!
We are also setting up a team to focus on just packaging related features within GitLab, like the Registry, which should improve our velocity in this area.
Package encompasses both the Container Registry, as well as other repository types like Maven, NPM, etc.