I don't think Nintendo has the ability to drop another Splatoon-like bombshell this year- I'd be happy with more traditional franchises like Paper Mario making an appearance.
But honestly, there's nothing left to focus on for some of those titles. XCX could maybe have some English voice acting but aside from that we know everything there is to know about that game aside from a release date, and I can't imagine Mario Maker being a huge focus- they can only show modes and neat features. If they honestly think E3 is the place to talk about games that are ALREADY OUT like Smash Bros., they're underestimating the event. The truth is, Wii U already has a great lineup this year IF XCX comes out in 2015. If it doesn't, then I don't really think Nintendo has a core, powerhouse title in its roster- Devil's Third is too niche, Fatal Frame is too niche, Wooly World is too standard, and there's no way Star Fox is going to be a full game.
Also, Pokken ain't coming to consoles before they have milked the arcade crowd dry.
I find it funny and sad that Nintendo has essentiall abandoned developing anything outside of eShop games for 3DS in favor of Wii U. Now I'm dissatisfied with both platforms.