My take is that the heavier boats are easier to sail imperfect. The wing mast and low momentum in an A-class means that you simply stop when sailed imperfectly-- that means no relaxation. There are only a few controls on an A-cat, but they must all be set correctly-- when the conditions are shifty or changing, an A-cat is a lot of work. You simply don't get home in an A-cat if you are not actively sailing-- you just stop; while most heavyweight cats can be sailed like beach resort rental boats and eventually get home.