Technically, you don't need the resistors if you're not trying to limit the current.
If you feel you need a sensing resistor, then you need to put a potentiometer in to start, and find out where the cut-off is, and what value works best.
The data sheet says to use filter diodes to protect the motor controller from back EMF from a motor. Would a similar setup between a wire wound resistor and the motor do the same, or just be a pointless exercise?
Diodes are usually used because they allow current flow in only one direction. Your resistor will allow current flow in both directions, possibly resulting in the resistor getting very hot and killing your power supply. Just where are you planning to put the resistor?