Swamp-hen is of course now the preferred name for Old World members of Porphyrio, though using it for the whole genus would reintroduce the same problems that helped lead to it being adopted as such, now that Porphryula has been subsumed into Porphyrio. Europeans who have just got our head around referring to P. martinica as just 'Purple Gallinule' rather than 'American Purple Gallinule' would then have to start using 'American Purple Swamp-hen', which sort of defeats the object.
In a global context, 'Gallinule' is preferable to 'Moorhen', much though I like the latter. Moorhen is potentially confusing even within Britain, as G. chloropus is not a natural inhabitant of upland moorland, but instead the low-lying grass 'moors' so common in my part of the world, intersected by drainage ditches (or 'rhynes') which provide perfect habitat for our 'Moorhen'.
Niels, as ever, drags us back to the original question, but while I can see his point, I still disagree. For academics and amateur birders interested in these issues, it is easy enough to distinguish it is Species A sensu lato or sensu stricto that is being discussed, both from the date of the paper and the geographical area. For the amateur birder not interested in taxonomic matters (other than perhaps for listing purposes), the global context is only going to arise a very few times, and keeping the 'local' common name will be far less disruptive than inventing a new common name that no-one has previously used.
All the best,
Julian