It may make more sense to use only %name for docdir, not %name-%version: it makes file links less volatile. Debian project may have had more discussions on that. Ideally, the behaviour could be controlled by some additional macro (multidocdir? :) for easier use in packages which are designed to allow simultaneous installation of several versions.
tracked at https://bugs.launchpad.net/rpm/+bug/911005
Looks like it's been accepted in fedora: http://fedoraproject.org/wiki/Changes/UnversionedDocdirs
ldv: ping?
There was a time when I wanted this so much, because with each update of some packages invalidated a useful portion of my bash and browser history.