I am not necessarily opposed to the addition of a
simple/non-namespaced relation, but it still seems like it should be
necessary to have some the relationship clearly articulated enough to
delineate between "hub" (or whatever relation name that is used) and
the existing "monitor" relation. A developer (like me) should be able
to make an informed selection between the two for other notification
formats.
At the very least, where there are overlapping relations (e.g. prev vs previous, hub vs monitor, etc.) we should indicate which one is preferred, perhaps by deprecating the other(s).
I appreciate Robert's concerns however and you can be quite sure that we'll see more rather than less specs developed behind closed doors before being unleashed on the world (Google Wave comes to mind). In that case I would suggest that they supply a URI relation in addition to the proposed short relation - reference implementations can send the URI and clients can accept both in the interim.
Whatever we decide the Web Linking draft needs to reflect it (and probably needs to go to some lengths to explain that URI relations are not evil).
Sam