Wii U has a nice elevator pitch – console plus tablet – but it doesn’t have a piece of software that effortlessly demonstrates the potential of that pitch. This morning in Japan, Nintendo unveiled the best and most intuitive example of the power of their dual screens that I’ve seen: a Google Maps app that lets you use the GamePad to navigate the beloved Street View while the overhead map stays on the television screen. The app will arrive in Japan in January; here’s hoping we get it in the States. It’s useful, it’s broadly appealing enough to serve Nintendo’s…