I think something from THQ is pretty much guaranteed. Darksiders 2 is coming, Metro: Last Light seems to be coming, and obviously Homefront 2 is coming. THQ is banking on massive Wii U support, latching on to new system hype, to help dig them out of their financial hole. Makes sense, so yeah. Given THQ's backing of the system, and Nintendo's promotion of third party titles, I'd put money on something THQ related showing up.
That doesn't mean it will be exclusive, timed or otherwise, or even have exclusive content though. Could simply be a multiplatform title demonstrating the value the pad can add to a game found everywhere else, or the first 'reveal' of a new game (eg: Homefront 2).
Either way, I bet they'll be there.
Dunno. Metro isn't a big franchise I predict Last Light will sell like ass. Cytek's Call of Duty clone seems like the right class of silly Nintendo would want at their conference. Crytek and CryEngine 3 are much bigger names than 4A Games.