So there is no confusion, I far prefer flying pattern over IMAC. I did IMAC for a spell and have not touched my big Extra for a long time. I like the 2 by 2 rule and the look and style of pattern planes. I am just lost when it comes to understanding why we weigh one plane with its fuel and the other without.

Take a plane filled with fuel (5kg empty) and make that the max weight, with fuel or batteries. Or keep it 5kg but weigh both ready to fly. As I already noted above FAI changed the heli/F3C rules to do this. They also increased the weight limit. They limit the swept area of the rotor disk, have no IC engine restrictions and limit electric to 51 volts (~ 12S lipo). Oddly, F3C helis have not grown in size, the swept area limits that, not the weight.

Keep the rules for size, sound, voltage, etc. To my feeble mind the way you keep the plane size stable is by not changing the size of the plane that is allowed. 2 meters is 2 meters. Period.