Reason the Wii U has been such a flop #2135
We're approaching two years on the market and Nintendo have only bothered to create two new IP's for the system. There's Nintendoland, a mishmash of existing franchises that has done relatively well and the Wonderful 101, loved by a small community (including myself) but rejected by the wider market. There are several reasons the lack of new IP's is killing Nintendo as a brand.
1) The success of the Wii was built on its unique new software. 13/20 of the top selling games on Wii were new IP's. 15 if you include the Mario Galaxy games. One of the reasons the Wii sales declined so dramatically later in its life was the lack of investment in new games by Nintendo.
2) Nintendo's traditional IP's are in decline. The popularity of Mario, Pokemon, DK et al. is falling and Nintendo aren't doing anything to change the formula of these games to increase interest again. Mario Kart Wii was a huge success because it offered an entirely new way to play a racing game. New Super Mario Bros. Wii reinvented the Mario formula to a modern take on 2D gaming. The Galaxy games added a whole new dimension and scale to 3D platformer mechanics. Mario Kart 8, NSMBU, Tropical Freeze, 3D World, Wii Fit U etc. are just iterative upgrades to existing games on previous systems. They're not bringing in new players and existing fans are seeing little reason to upgrade.
3) Nintendo is turning itself into a niche developer. The lack of new IP's is giving the general public the impression Nintendo is just a Mario production line and if you aren't interested in those games there's no reason to own a Nintendo system. Whether such an impression is fair or otherwise, the lack of investment in new IP's is having that effect.
4) Focusing exclusively on the narrow range of game genres covered by existing IP's will alienate a huge portion of the market and make the conditions for third parties unsustainable. We've already seen this happen, where unless it's a 2D platformer or kart racer, third party games will flop on the Wii U. Nintendo need new IP's to attract different audiences to their systems and allow third parties to find success on the platform with their games.
Ultimately, I can't understand why after the huge success of creating new IP on the DS and Wii, Nintendo would just completely abandon that policy and replace it with just pushing out the same old games with small improvements. Bring on Splatoon.
1) As said earlier, only 7 new IPs in the top 20 on Wii and most of them were just for using Wii hardware
2) Nintendo IPs are not in decline. You shouldn't consider too much numbers from Wii and DS games, these are not really relevant. Super Mario, Mario Kart, Smash Bros, Pokémon, Animal Crossing, Zelda... it's as strong as it was before.
3) and 4) Splatoon (TPS), Xenoblade (RPG), Pikmin (RTS), Fire Emblem (T-RPG), Animal Crossing (Life Sim), Smash Bros (Fighting), Advance Wars (TBS), Zelda (Adventure), Star Fox (Rail Shooter), Metroid Prime (FPS), Kid Icarus (TPS/Rail-shooter), etc... Nintendo is not just Mario. They may have too many platformers, but it's hard to stop a serie when you have Super Mario, Donkey Kong, Yoshi and Kirby. Captain Toad is something completely different.
I think most Nintendo fans are good with Nintendo IPs management, and that's the most important thing. Attracting "casual" players is not that important, and a 15/20 million players fanbase is not what I would call "niche".