Change the Motion Sensor from being a gadget to being a piece of equipment instead, such as grenades. The motion sensor is really weak due to how the game plays and how the gadget itself works. Making it a piece of equipment that some classes can use would make better use of the gadget.
Another option to benefit the Motion Sensor would be to make it to where enemy players were marked whenever triggering a Motion Sensor. This would make it more powerful to fit a gadget role.