I love my Wii U. I love the games for it. I love the amount of support Nintendo gave for it when times were rough for the system. All this talk about the NX (which we really still know nothing about) makes me sad that the fact that the Wii U is widely considered a failure when it had so much potential in terms of gameplay and unique control schemes.
WarioWare would have been an amazing party game utilizing the Wii U gamepad. Imagine passing around the Wii U gamepad around the room for microgames. Imagine the possibilities of asynchronous multiplayer for the microgames. The gyroscope, touch screen, and camera all could have been great for micro games for the system. While it could have been great, I understand that Intelligent Systems was busy with A LOT of games during the span of the Wii U's life and with the resurgence of the Fire Emblem series they have been super busy I assure.
Mario Party series has dropped dramatically in frequency of releases since the gamecube era. And the series needed a good break to come back fresh (and because of change of developers) but Mario Party 10 was not the way to go. Personally for me, the biggest draw from the Mario Party series was screwing your friends over, having a bunch of random interactions on the map, and fun minigames. From what I heard the mini games are decent in Mario Party 10 but the "everyone in one car" bullshit really took a damper on the fun. Last year me and my friends replayed Mario Party 5 on the gamecube and had a blast. We played Mario Party 9 right afterwards and the magic just wasn't there. This is really disappointing because motion controls are great for this type of game and the series is going to have a rough time moving forward without them.
Many people are bummed out by the default control scheme for Star Fox Zero, but Pilotwings would have been perfect for this. Using the gyoscope in the gamepad would have been great for controlling aircraft and honestly this could easily have been a digital only title or a budget release that I doubt would take Nintendo long to develop for.
Mario sports games. I always loved the idea of the Mario sports games because they took very traditional game elements like Tennis and Golf and gave them RPG elements and unrealistic game types. With the Wii U having a much better online infrastructure than the Wii, there could have been great online matches for Super Mario Strikers, Mario Golf, or Mario Baseball. Nintendo could have easily licensed out these series to 3rd party dev because we've seen when Nintendo rushes out a Mario Sports game with Mario Tennis Ultra Smash. These are not the huge money making series like the mainstream Mario games, so I don't see why Nintendo shouldn't farm these title out to other developers so that their resources won't be used up, can have a genre that's almost non existent on Wii U, and have games to fill the void for times when they've had game shortages.
Sin & Punishment sequel & on-rail shooters. The death of motion controls will also be the death of on-rails shooters. The Sin & Punishment sequel was only possible with the re-release of the original on the Wii virtual console shop. And the controls of Sin & Punishment Star Successor worked perfectly for motion controls. The same with games like Dead Space: Extraction and House of the Dead: Overkill. If Nintendo wanted some more mature games a sequel to House of the Dead: Overkill should have been a no brainer. Nintendo is not shy of having a marketing deal with Sega and given how motion controls have practically died from this generation a House of the Dead sequel would have been an exclusive game that only the Wii U could provide.
Sequels to the Operation Rainfall games. We got a sequel to Xenoblade Chronicles, and that's great, well what about Pandora's Tower and The Last Story? Both were critically acclaimed games for the Wii. The developers for The Last Story hasn't developed anything worthwhile since The Last Story was released and Nintendo could have easily scooped them up for a sequel to fill in the gaping hole of RPGs for the Wii U. The developers for Pandora's Tower have been pretty busy but Nintendo could have at least place the foundation for a sequel for this game.
A clear given for a small downloadable title is a Pokemon Snap game. The Wii U's gyroscope would be perfect for this and its a shame that it'll never be utilized. Since I'm talking about Pokemon, a pokemon RPG in the vain of XD would have been great to fill the gap of RPGs as well. The last gen was released in 2013 and that would have gave Nintendo more than enough time to get a developer for a game based off of this gen.
There's a ton of games that Nintendo could have followed up on that were successes on the Wii and could have been great sequels on the Wii U from third party developers: Red Steel 3, No More Heroes 3, Capcom vs Tatsunoko 2, Zack & Wiki 2, Muramasa: The Demon Blade 2, Trauma Center series. All these titles could have been exclusive deals to bring more 3rd party content to the Wii U. And some of these titles like Zack & Wiki and Red Steel could have benefited from the available control schemes for the Wii U.
Let's just assume that Nintendo's next console doesn't involve motion controls and instead goes for a more traditional control scheme. We could be losing out on a lot of great things and It frustrates me that Nintendo didn't look outside of their own development teams for help for software on the Wii U.
tl;dr: The Wii U could have been much better software wise if Nintendo focused on outside devs to help fill out their software gaps instead of doing absolutely nothing.
WarioWare would have been an amazing party game utilizing the Wii U gamepad. Imagine passing around the Wii U gamepad around the room for microgames. Imagine the possibilities of asynchronous multiplayer for the microgames. The gyroscope, touch screen, and camera all could have been great for micro games for the system. While it could have been great, I understand that Intelligent Systems was busy with A LOT of games during the span of the Wii U's life and with the resurgence of the Fire Emblem series they have been super busy I assure.
Mario Party series has dropped dramatically in frequency of releases since the gamecube era. And the series needed a good break to come back fresh (and because of change of developers) but Mario Party 10 was not the way to go. Personally for me, the biggest draw from the Mario Party series was screwing your friends over, having a bunch of random interactions on the map, and fun minigames. From what I heard the mini games are decent in Mario Party 10 but the "everyone in one car" bullshit really took a damper on the fun. Last year me and my friends replayed Mario Party 5 on the gamecube and had a blast. We played Mario Party 9 right afterwards and the magic just wasn't there. This is really disappointing because motion controls are great for this type of game and the series is going to have a rough time moving forward without them.
Many people are bummed out by the default control scheme for Star Fox Zero, but Pilotwings would have been perfect for this. Using the gyoscope in the gamepad would have been great for controlling aircraft and honestly this could easily have been a digital only title or a budget release that I doubt would take Nintendo long to develop for.
Mario sports games. I always loved the idea of the Mario sports games because they took very traditional game elements like Tennis and Golf and gave them RPG elements and unrealistic game types. With the Wii U having a much better online infrastructure than the Wii, there could have been great online matches for Super Mario Strikers, Mario Golf, or Mario Baseball. Nintendo could have easily licensed out these series to 3rd party dev because we've seen when Nintendo rushes out a Mario Sports game with Mario Tennis Ultra Smash. These are not the huge money making series like the mainstream Mario games, so I don't see why Nintendo shouldn't farm these title out to other developers so that their resources won't be used up, can have a genre that's almost non existent on Wii U, and have games to fill the void for times when they've had game shortages.
Sin & Punishment sequel & on-rail shooters. The death of motion controls will also be the death of on-rails shooters. The Sin & Punishment sequel was only possible with the re-release of the original on the Wii virtual console shop. And the controls of Sin & Punishment Star Successor worked perfectly for motion controls. The same with games like Dead Space: Extraction and House of the Dead: Overkill. If Nintendo wanted some more mature games a sequel to House of the Dead: Overkill should have been a no brainer. Nintendo is not shy of having a marketing deal with Sega and given how motion controls have practically died from this generation a House of the Dead sequel would have been an exclusive game that only the Wii U could provide.
Sequels to the Operation Rainfall games. We got a sequel to Xenoblade Chronicles, and that's great, well what about Pandora's Tower and The Last Story? Both were critically acclaimed games for the Wii. The developers for The Last Story hasn't developed anything worthwhile since The Last Story was released and Nintendo could have easily scooped them up for a sequel to fill in the gaping hole of RPGs for the Wii U. The developers for Pandora's Tower have been pretty busy but Nintendo could have at least place the foundation for a sequel for this game.
A clear given for a small downloadable title is a Pokemon Snap game. The Wii U's gyroscope would be perfect for this and its a shame that it'll never be utilized. Since I'm talking about Pokemon, a pokemon RPG in the vain of XD would have been great to fill the gap of RPGs as well. The last gen was released in 2013 and that would have gave Nintendo more than enough time to get a developer for a game based off of this gen.
There's a ton of games that Nintendo could have followed up on that were successes on the Wii and could have been great sequels on the Wii U from third party developers: Red Steel 3, No More Heroes 3, Capcom vs Tatsunoko 2, Zack & Wiki 2, Muramasa: The Demon Blade 2, Trauma Center series. All these titles could have been exclusive deals to bring more 3rd party content to the Wii U. And some of these titles like Zack & Wiki and Red Steel could have benefited from the available control schemes for the Wii U.
Let's just assume that Nintendo's next console doesn't involve motion controls and instead goes for a more traditional control scheme. We could be losing out on a lot of great things and It frustrates me that Nintendo didn't look outside of their own development teams for help for software on the Wii U.
tl;dr: The Wii U could have been much better software wise if Nintendo focused on outside devs to help fill out their software gaps instead of doing absolutely nothing.