I think that the SL16 will definitely revitalize interest in youth multihull sailing. It is definitely time to move forward with a new boat. Kids know the current trends better than we do, just look at the 29er and 49er sailors out there.. They are not racing CL16s maybe sailing them at sailing schools..)
(or pick any older boat) any more for a variety of reasons including the fact that the newer designs are more fun and more exciting and easier to sail..
As to the SL16 being relevant to other classes..well any change to cat sailing that brings fresh new interest from youth sailors is very welcome.

Yes the cost is a factor since there are no used ones in north america..but that will change. The top teams will always buy new boats anyway and these will take a couple of years to trickle down to the rest of the fleet as used boats.

I don't think that anyone said that the SL16 would be competing with other classes..F18, F17 etc.