It's difficult to say. On one hand, Splatoon has that Mario Kartish quality of being both complex and simple in a way that allows for broad appeal. On the other hand, Xenoblade Chronicles X has more traditionally mainstream aspects: its open world, the combat, the SciFi setting the art style (character models not withstanding), the online functionality. SciFi open, open world, and RPGs are pretty big right now. So they both have their strengths. And if there's a price cut to the Wii U, it gets even more competitive. And I am not sure which game would benefit more from that price cut.