There are 2 things you may not be aware of.
The things you can do to a silver can motor to make it perform better are numerous. There was one person who was able to get a silver can motor to out-perform a ROAR stock 27 turn motor. Look up red dot motors. Even with Tamiya's RPM limit, it was still too much of a guessing game with motors.
Since the advent of brushless motors, most TCS racers wanted to shift to brushless. But as we have found out even brushless motors can be tinkered with. So the call went out for Tamiya to come up with their own brushless motor and ESC. Tamiya hasn't come up with anything. So after careful consideration (at least I hope careful) Tamiya USA decided on a high quality spec motor for TCS racing. Reedy has been a motor manufacturer for a long time. I just brought one of the motors and the quality is very good. Much better than the cheaper motors that are out there, and will hold up to the rigors of racing.
The problem with rules changes is someone is going to be pissed. Fred doesn't make changes without thinking it through. This motor change is a step in the right direction to make TCS racing more equal, and therefore more fun.