According to CVG, the next 3D Mario platformer will release sometime by this October. Reportedly, Nintendo has been discussing their release strategy to retailers in the executive level to help boost confidence and reassurance about the struggling Wii U system.
A massive Wii U marketing campaign is being said to launch once E3 hits, leaving the second half of 2013 with a strong lineup of games. Games like Pikmin 3, Wind Waker HD, and The Wonderful 101 are all expected to hit in the second half. With Mario Kart being said to be released by the end of the year and the news that Super Mario U will be out by Octover, the Wii U will have a lineup stronger than previously thought.
Super Mario for Wii U and Mario Kart will both be playable at E3. Nintendo plans to announce many of its plans in the coming weeks as we inch closer to E3 this June 11.