This has been stated before, but a decent percentage of people avoid 1/12 completely due to the need for all the 1/12 specific components (1s batteries, 1s speed controls, mini/micro servo's).
To help 1/12 mod, those in charge should consider opening up the rules to allow racers to use either 1s or 2s batteries. This will make it easier for guys from other disciplines, like off-road, to give 1/12 a try.
I also agree that 13.5 is too close to 17.5. So instead of 13.5 how about open motor & blinky esc. Again as stated above allow the choice of a 1s or a 2s battery.
Just for another perspective, I've raced H.O. scale slot cars for 20+ years and have seen all sorts of different classes proposed with spec motors. Each one was supposed to be the new savior of the sport, but every single one of these became a motor war, and other than their 17.5 equivalent they all either disappeared or went back to open motor.