you could still perhaps override core perl modules with these kinds of RPMs, you can't really install two concurrent ones (ie, perl-Foo-1.1 and perl-Foo-1.2) since they would conflict over docdir.
Are you talking about /usr/share/doc/*? On my FC2 installation, the subdirectory names in that directory have both package name and version, so multiple docdirs can coexist. That hasn't changed since FC2, has it?
