I don't think that you'll get the 13.5 to be "on par" in some of the classes. On a roadcourse in 12th the 13.5 is way faster at the 6 minute mark because it doesn't fade as much from heat.
In the end, we need to get all of the motor manufacturers to agree on a "stock" brushless design and stick with it. Everything should be locked down from the wire to the rotor.