I think it'll be very hard, if not impossible, to find an unambiguous definition for any genre or subgenre (which is why ever more sub-subgenres are springing up - and the other reason is that any setting now demands becoming its own genre... but I digress). See High Fantasy, who I had thought was pretty unambiguous, until one tries to use it to define Low Fantasy, and suddenly LF's ambiguity seeps back into HF instead of the other way around...

Maybe the best compromise would be to provide this exchange's definitions for the more controversial subgenres prior to or along with nominations?