What determines if a design is better for lightweights or for heavyweights? I guess the hull sections and rocker have influence but without going into the finer points of naval architecture why? I can understand that a design suited to "lightweights" isn't going to be very quick if sailed by a heavyweight crew due to increased wetted area. Is it the same the other way round, will a light crew be slow in a "heavyweights" boat? If so why? Any thoughts, educated or otherwise.
There aren't really any bad boats for lightweights these days.
There have been boats that worked much better heavy weather and for these, only very light people could ever get them to go in the light. Baggy 2 and Street Legal. The flip-side to this was that the lightweights often didn't have the power to get the best out of the hull shape when it blew old boots.
No-one sails really heavy these days anyway - it is a lost cause!
In short not an issue unless you are looking at buying a Baggy 2, a Street Legal or a Radical Posture...