Maybe one first-party Wii U game will be announced, like Yoshi's Island, but don't expect anything big. It'll most likely be new trailers/ info on already announced games like Pikmin 3. Nintendo always saves big reveals for E3.
Nintendo also needs to give some clarity on when all these big 3DS games are coming to the West... Luigi's Mansion, Fire Emblem, and Animal Crossing all are promised before June 2013. That's one new game roughly every eight weeks.
Broadly speaking about 2013 in general... it's about time for Alphadream to be ready to talk about Mario & Luigi 4, and Nintendo should be able to say at E3 whether they've finally made up their mind to make a sequel to Link to the Past, a Majora's Mask remake for 3DS, or both. Either way, if Grezzo is making Majora's Mask as they did OoT, late 2013 launch should give them a nice two year development cycle.
