Commit 2e88d11 suggests that dbus-glib-1.pc mentions GLib and DBus. That’s one of the two criteria that we use to add propagate inputs. So that part of the commit is OK.
As for removing DBus and GLib as inputs of the other packages, it’s really a question of whether the package uses them directly or not, as Mark wrote. This would need to be checked for each of them. The conservative approach would be to leave DBus and GLib as inputs until we have evidence that the package in fact only needs dbus-glib. Should we revert that part of the commit, at least for packages for which we don’t know? Thanks, Ludo’.