Leave the sensor bar in the box if you're only playing singleplayer games on your Wii U.
New Wiimotes for the Wii U feature design improvements such as an external sync button.
Wiimotes and other accessories getting Wii U treatment later this year.
While the Wii U supports the Wiimote with Motion Plus, Nintendo isn't forcing developers to use the new technology.
Nintendo is considering to offer several Wii U models at launch with bundled Wii accessories such as the Wiimote.