As mentioned above, your speed is limited by the plastic rather than by the speed / power of the motors. Positioning accuracy will go up with things like fancy drive screws (except for their coarse pitch). Print accuracy (like speed) will be limited by the plastic coming out of the hot end. For a more accurate printer you would go to a 0.2 mm hot end vs a 0.4. With a small hot end like that, your full volume prints are going to take a *long* time. All screw drive is also not going to be very fast ....
If you run multiple motors simply for symmetry, the parallel approach works for them. You only need one driver per axis plus one for each extruder. There are a number of controllers that will do that quite well.
If you run multiple motors simply for symmetry, the parallel approach works for them. You only need one driver per axis plus one for each extruder. There are a number of controllers that will do that quite well.