Did anyone genuinely want Mario Tennis Ultra Smash? Doubt it.
Did we ask for X type of game. In this case yes a few people did want a new Mario Tennis game. I certainly did. I loved Power Tennis and wanted a WiiU sequel. The WiiU game turned out to be so bad I didn't buy it. If I'm saying that, it has to be bad. I actually did pre-order Ultra-Smash and then cancelled the pre-order. I'd glad I did. If I can get the game for $20 on sale I'll get it. But otherwise it'll stay on the shelves for me.
People did want a WiiU Mario Tennis game. The game just happened to be so bad no one bought it.
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Animal Crossing Happy Amiibo Festival - take away the fact that the game is pure garbage, no one even wanted this concept. Something like the Mario game Fortue/Boom Street is a way better game. An Animal Crossing borard game. No one wanted it. A terrible concept.
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Splatoon - Lets ask for a family friendly overly bright and colour saturated shooting game to be made said no one ever apart from Nintendo. No one was asking for this concept before it came out. It turned out to be an amazing concept though, done very well. Proof that just because no one is asking for a concept, that doesn't mean the idea is bad. New ideas can be good as well.
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WarioWare Inc. - Another concept no one asked for. In the games it's done well, it works and has had moderate success.