I imagine Nintendo will be the first to market in early or mid 2012. The 'Super Wii' will probably be about 2.5x as powerful as the PS3, using a proprietary format based off of HD-DVD or Blu Ray to store games. I imagine an integrated online system with one single friend code for each hardware. I also expect Saturn/Dreamcast/Gamecube games to arrive on the next gen Virtual Console and WiiWare to have a significantly higher size limit (1GB?)
I think the other two consoles will be launched slightly later in 2013, they will be about 3-4x as powerful as the PS3, meaning there is a graphical gap between the 'Super Wii' and the others but not as big as this gen. I think both will have a moderate level of motion control integrated.
I also expect the industry to become more polarised - with Japan primarily supporting the 'Super Wii' and handhelds and the West supporting PS4 and 720.
