I think most people who watched Nintendo's Digital Event this year were somewhat unsatisfied. This is the main lineup Nintendo had at E3 with three additions of my own - Super Mario 3D Galaxy, The Legend of Zelda: Twilight Princess HD, and an untitled Metroid game, all for Wii U. I feel that something like this would have made Nintendo at E3 much more impressive.
Other possibilities include:
-A new F-Zero game or F-Zero GX HD
-Golden Sun for 3DS
-Pikmin for 3DS
-Pokemon Snap 2
-Pokemon Tournament for Wii U
-More Mario Kart 8/Super Smash Bros./Splatoon DLC
Enjoy! Don't forget to share your own ideas in the comments.