[BP-Revo]

From what I know, a motor always generates some sort of energy when it is used as a brake. If johnrobholmes is correct, it seems that Castle takes the energy and puts it back into the battery (which I actually don't think is right, because this on a freshly charged Lipo might damage it - I think it just puts it into the caps or something), then it means the ESC takes the grunt to save the motor. Other controllers might make the motor take the grunt to save the ESC (by shorting out all the motor leads).

Brain, regardless of how many Fets take the current under braking, if the braking causes voltage to increase X amount over the current input voltage from the battery, and X is too much for the Fets, the Fets pop. Having 1000 Fets each rated for 25V, all 1000 will pop if you put 30V through them (I'm saying this for exemplary purposes).

Personally, I don't think it would be a bad idea to have some sort of super capacitor attached to the ESC that would absorb all the energy created under braking. This energy can then be put back into the ESC when throttle comes back on. Obviously, going 40-10mph is going to generate a good bit of energy, much more than a few ~300-400uf capacitors will take. Maybe if they had a few 10000uf capacitors in parallel (even if they were a bit large compared to the average cap) I'm sure it would help quite a bit.

One thing I DON'T understand about ESC's is why adding capacitors help with keeping temps down. From what I understand, it just helps keep the input voltage more constant (higher, when you are on the throttle). Wouldn't this cause the ESC to work harder, and thus run hotter?