RPM now supports weak dependencies, information here:
http://www.rpm.org/wiki/PackagerDocs/Dependencies

Also, rpm Dynamic dependencies are currently in development:
http://www.rpm.org/wiki/DynamicDependencies

Depcheck needs to support these new features so that when packages within Fedora begin to use them depcheck will be able to properly handle them.

First, need to add functional testing to test these features. This requires updates to rpmfluff to proceed:
https://bugzilla.redhat.com/show_bug.cgi?id=1253059

From here, further development depends on results of running these functional tests.