There's always the possibility of the people who bought this game for the Wii U bought the Wii U itself exclusively for this game and picked other stuff on the side. Maybe they still bought the Wii U version because they didn't want to feel as if they wasted money on the console when this is the game they bought it for in the first place.
Although I didn't think it would have had much of a following as a system seller. Exclusives sell more. Even though it went multiconsole, it still sold. I think more developers should do this on Nintendo consoles. Say they're going to be exclusive, then a few months later say they're going multiconsole. More sales from Nintendo fans thinking it was originally going to be exclusive, more sales from people who get it for the other people. Their games would actually sell on Nintendo consoles this way.











