I like your approach. Test it on the field. I have tested the caps on dyno as well because I couldn't fell much of a difference on the track. One thing I would like to clear, is about the smoothing of the power. Because the ESC works with pulse width modulation, there is no smooth power. Power is the product of voltage and current, and the current is constantly switched on and off by the ESC to the motor. However what the capacitor does, is that it smooths the current flow from the battery to the ESC. So even in the off-period there is current flowing from the battery to the cap. Then on the on-period the ESC sees a lower impedance level because of the cap and the battery voltage drops less. This is the key! While pulsing the current to the motor, the battery voltage during the on-period is kept higher. Whenever the trigger is pulled all the way in for maximum power, the pulse width reaches 100% and there is no more pulsing of current, because the current is constant. Therefore the effect of the capacitor is eliminated in a few microseconds. For the capacitor to actually aid in the acceleration at full throttle, the capacitance would have to be several tens or hundreds of Farads.
The effect of the motor drawing more or less current depending of the position of the armature of negligible in this case.
So what does the cap do then? It improves the efficiency of the battery at partial throttle resulting in more power, but only at partial throttle. If you find anything else on the track that works for you stick with it.
BR/ JesseT