Not really sure if I should put this here or in the Wii U topic but here is some Sonic Dimensions rumors.
- working title
 - takes place directly after Generations
 - spiritual successor to Sonic Colors
 - visual quality in line with Generations
 - will take advantage of many Wii U specific capabilities
 - includes the use of the Wii U controllers for up to a 4 person multiplayer
 - use of touchscreen to destroy enemies and activate powers
 - storyline will center around another time-space continuum shift at the hands of Eggman
 - this alters Sonic’s world and Sonic himself
 - Sonic will allegedly split into multiple personalities denoted by color
 - each color has its own unique abilities
 - blue Sonic will be the core Sonic, and will be the uniting figure with the other colors
 - five other colors: Red, Orange, Purple, Green, and Yellow
 - Red Sonic can cause explosions to open up new areas, but has a slow speed and a short jump
 - Purple Sonic will be able to move platforms and float and will have a dark attitude
 - Orange personality similar to Big the Cat
 - yellow Sonic will be the fastest of them all, but takes damage easily
 - only two of the personalities can be used in-stage
 - all may be able to combine and act as an equivalent Super Guide
 - White Sonic allegedly pops up as an option after dying in a stage a certain number of times
 - using White Sonic will make the game easier, but will give you a low rank
 - SEGA may be working with Nintendo developers on this game
 - includes most of the Sonic Colors staff
 - Nintendo helping with level design, which will take a more surreal approach
 - Music Plant from Sonic Advance 2 may be revived for this project
 - Rival battles: fight evil versions of friends like Amy Rose
 - Eggman's personality will split, making a nice version
 - classic Sonic-style 2D elements
 
Most noteworthy things from this rumor is that it will use the Wii U controllers for 4 person multiplayer,Nintendo might be helping out Sega with level design, most of the Sonic Colors team will be working on this title and the Clasic Sonic-style 2D elements will be there. As far as I know there hasn't really been any hints as if any games will use 4 Wii U controllers or not. Question is does this game support 4 Wii U controllers or a mix of Wii controllers and Wii U controllers.