I raced cars in a new class of racers called "Showroom-Stock". Complaints were eventually raised that some racers were able to "shop" dealers' inventories for the best parts and "Showroom-Stock" cars got rebuilt drivetrains—with those best parts—before they hit the track. I did OK, but the class was doomed by $ponsorship$. I readily beat the delightful lady-racer Lyn St. James, (most recently with Ford at Indy 500 and CART), but mostly because she couldn't keep her GM Cosworth-Vega running!"...My guess is that since Racers are such an important market they will not deviate from a totally class legal boat in any way. China does have quality control problems but looking at older Sunfish I'd say the quality varied widely from boat to boat and manufacture. Today's manufacture quality should be far above yesterdays processes. All in all racers should come out the winners.
If new Sunfish come out of the chocks with totally class-legal boats, racers would already have a head start over the older boats. That said, selecting the right older boat, and "tweaking" the bottom to limit flex could put the (many available) older boat(s) ahead. Including mine! With time, such standardization with new injection-molded hulls certainly ought to settle the question of fine-sanding the hull.