The Wii U is basically the Wii 2 so it's only natural that it would have super graphics. Some upcoming and potentially some currently released Wii U games have been confirmed to be in 1080p and 60 FPS, which is something the Wii I don't think is able to do or at least hasn't done due to hardware limitations. Also, the Wii U plays Wii games in addition to Wii U games, so there's no reason to really use your Wii anymore unless you care about GameCube games or using the GameCube controller for a game like Super Smash Bros., Mario Kart 7, etc.