While I would love it, I don't think that Nintendo will show off a new Metroid this year if it is in the works. I think right now the last thing that Nintendo really wants is another Zelda U situation on their hands. They showed off a game far too early in development and put an unreasonable release date on it, then the internet exploded.
If I had to take a guess, we might hear something about Monster Hunter 4 being ported to Wii U for the holidays, possibly SMTxFE(although that would make 2 FE and SMT games in one year, so maybe not), maybe even Animal Crossing U. I am pretty confident that we'll see more of Star Fox and something else big, but I really have no clue what.
“What I say is, a town isn't a town without a bookstore. It may call itself a town, but unless it's got a bookstore it knows it's not fooling a soul.” - Neil Gaiman
