At one point in time a 73 inch plane was just fine for IMAC, I still fly my 68 inch Extra that was an IMAC plane years ago. A couple things happened, first, all the judges went blind and can no longer see anything smaller then a 40% planes, no laughing, this is truth. The second thing was pilots discovered the bigger planes were much smoother and they could score better with them.
The advent of much stronger and faster servos and better electronics also allowed pilots to remove all the added servos required to make the controls go Flippy Flop. How well the plane is set up is now key to how well it will perform.
A Question for Shawn: Have you tested any of the new high torque Chinese servos to see how well they perform?? Not doing any competition flying I see no need to be buying the high end servos these days but as a sport pilot in need of new servos I'm tempted to give those cheap digital servos a try. Wondering how they really perform??