Splatoon would have a difference in how people thought about the Wii U, perhaps. It would have pushed people to believe that Nintendo was committed to doing new things with their software instead of just their hardware. I think it would have generated a lot more attention. I think even Zombi U generated attention for that same reason. XCX is kind of the same, though with a much more niche audience.
Of course, they still would have followed it up with a line-up of new versions for the same games they've been making for decades and that spark of interest would have waned once more.
Mario Maker is great for hardcore 2D Mario platforming fans but is it something most people care about? I don't think so. It's for the existing Nintendo faithful. I watched a video of a level someone made and I thought, "wow, that's creative," but I had absolutely zero interest in playing it or in designing my own.
