I can see the point regardig sail development, the F18 class is a newer generation so it has the upper hand in that.

Interestingly the Infusion hasn't changed sail design since 2006 so its not like a continual evolution, just steps..

It should be possible for a new 20 to be viable, what if the carbon rig was swaped for carbon hulls? then you have a lighter platform, masts have come a long way since the old teardrops so an alloy section would be fine (as seen on the Singapore 20's)