While I'd agree that wheel inertia has little to do with steering, other than the capability to quickly turn the front wheel at low speeds to initiate the counter-steer roll action - the amount of inertia has an indisputable affect on the STABILITY of the wheel.
Simply put, the lower the inertia of the front wheel, the easier that assembly can be flicked from side to side. That is physics. No argument about it.
Now, consider how this affects the ability of the front assembly to resist any headshake or tankslapper instability. My guess? Any geometry/tire/weight motorcycle configuration that is close to borderline stability can become unstable given a much reduced inertia/gyro force from the front wheel.
I'd agree that in a normal tire/rotor/wheel design, without any specifically designed counter-rotating mass, and even with very light components such as carbon wheels and brakes, there is enough inertia/gyro force from the whole assembly (especially from the tire), to not present a problem. But, purposely negate the gyro stability altogether? I'd want someone else to be testing that on a high-speed bumpy road under hard acceleration!
