actually, F50 is a single design, fully shared specifics by the class association (and the club organizing the sail GP), which would be great for the competition and would have all the teams on the same level
it's true that a 6-man crew is very demanding in terms of boat/quota places, but at the same time cutting kite and mixed dinghy (at least 80, maybe 100 spots, didn't make the exact count) and reducing a bit the enormous amount of ILCA spots (let's say 5/6 places less for both genders) might do it somehow (20 F50 crews = 120 spots, not too many more than those that would go with the other 3 classes out)
about the 3-man crew match racing event, we had that in 1992 with the soling class and it wasn't really a good show...if match racing gets back, it has to be with the most spectacular boats and course available (which is the sail GP environment right now, I have no doubt about it)