Everyone knows that Nintendo has never really been focused on graphics, yet they win over consumers money by innovating games and game play. According to several anonymous sources, the Wii U will be capable of high-definition graphics, but it won't be able to keep up with the Xbox 360 or PS3 due to a lower amount of shaders.
Price will be a major concern just like it was with the Wii. Price is why the Wii was able to keep up and even win the console war. Top quality graphics require a high price which Nintendo would like to avoid in order to appeal to a wide variety of gamers. Nintendo is trying to capture more hardcore gamers with the graphics update.
They also want to keep their innovation of control going with the introduction of the tablet controller. Additionally, the supposed release date has been leaked by a Japanese retailer. It is expected to release on 18 November in the US and a week later in Japan. Other regions don't have a specific date, but Nintendo has promised to get it out to everyone by the end of the year.