I agree with previous posters that in this case, the vehicle is pretty balanced as is. Adding the front motor would add weight and might be problematic for cable routing, extra battery, extra weight in the front wheel etc. If the rear motor is already getting hot, you'd need a new wheel with a new motor, a new battery and a new controller. At that point it's likely the brakes might be too weak, and the frame might be flexing too much.
In this case, getting a more powerful bike (or, likely more fun, a second scooter for your pillion) sounds like the best move forward.