Base a performance issue on how much room is on the starting line? How about a longer starting line based on the size of the boat and numbers present?
The 2.5m width max. I proposed is arbitrary and accompanied by a

and in any event, I don't think anyone with any understanding of sailing catamaran design would seriously contemplate a beam width of more than 2.5m on a 14ft boat, regardless of the transportation issues such a boat would present nationally and internationally. If you think I'm wrong convert a Hobie 14 and put a H16 rig on it see what happens. It's been done and it failed miserably because a H14 leeward hull needs more buoyancy to support the additional pressure that a bigger rig exerts on it and bigger hulls means heavier which means more displacement which means more drag which = slow. (box rule)
Incidentally, the optimal design wind speed for my 430 is 15knts with a 75kilo crew and it is designed to de-power itself to a degree as wind strength increases. It currently carries 5ft sq. less sail than an A class and will soon have a kite so I'm not sure exactly what you mean by;
The weather in Oz favors smaller, more efficient sail plans. Here in NA (where the class is currently forming) the winds are generally lighter and favor larger sailplans with the ability to detune the rig as the wind picks up. You can always furl sails your are carrying, but you can't unfurl sails you're not carrying.
Just what is the average wind strength in NA and what sail area would you consider to be optimum for a high performance 14ft cat, and are you suggesting that the design rules should suit one area?
Bern