Diesel electric propulsion is quietly taking over most large mobile applications. Even cars are slowly going gasoline-electric. Better magnetics would only speed up the switch.

Of ships it has what you stated, and you no longer have to build the engine on a incline to drive the propeller or have complex transmissions. Other benefits are you can have 2 engines and only run 1 during calm weather cruse. Also electric motors are able to be mounted in stearable pods, greatly increasing maneuverability of a ship (need fewer tugs to go into port). Some ships have nothing but the pods for good station keeping.

Multiple locomotive trains only need 1 engine, but run power to several for extra traction, and it enables things like traction control that can't be cheaply done mechanically.