Hey, I'm opening this bug for discussion. It'd be interesting to integrate packages.gentoo.org with repology.org service to immediately see the state of a package in its p.g.o page. Repology will show packages that are outdated in a repo, and even show if there are known problems with current in-tree versions (like security issues). However it might require some manual work to match some packages. For example, https://repology.org/projects/?search=edi&maintainer=&category=dev-util&inrepo=gentoo¬inrepo=&repos=&families=&repos_newest=&families_newest= when trying to search for dev-util/edi it still matches multiple packages. Most packages probably work out of the box pretty much. You can input category, package name and ::gentoo repo, which narrows search results a lot.
This was one of the intentions of the 'grumpy' project[0], which hasn't really got off the ground. If some of the back-end stuff could be sorted, it might spur some more development on that side of things... [0] https://gitweb.gentoo.org/proj/grumpy.git
This has been implemented some time ago. Thus I'm going to close this bug. Thanks again for the suggestion.