G,
There are 2 aspects to this. One relates to Vs, the other to the design max speed for the application of full aileron and rudder (which really is the main implication of Va for a pilot). I would want aircraft designed such that I could apply full aileron and rudder at the highest speed possible, requiring Va to be based on max TOW. Irrespective of what Va is quoted as, the N1 exceedance potential remains the same at speeds above "manoeuvre speed" or corner speed as it is referred to in combat aircraft.
L