I think Nintendo will be porting a lot of Wii U games to their next system. Just like how a lot of GameCube games were ported to the Wii. The result was a really good launch year for the Wii. It also lead to quicker development of Mario Kart, Smash Bros and even Metroid.
So 2016 at the earliest, and 2017 at the latest with a Zelda U port, 2D Mario, and a new multiplayer IP at launch. Metroid, Fire Emblem, Galaxy 3, Paper Mario, Advance War sequel, and a Mario sport game will release before its 2nd holiday sale. Smash Bros and Mario Kart will continue to release before the 3rd holiday.
I think we will see Luigi Mansion 3, Pikmin 4, and other A-AA games for Wii U's 2016 and the Wii U version of Zelda U after Nintendo 7's version launches. I'm hoping for a multiplayer 2D zelda for holiday 2015 as well.
edit: On second thought, we can see Metroid, Fire Emblem, Paper Mario, 3D Mario, and a Mario Sport game in 2016 as well. But these sequels on the Nintendo 7 will have modest graphic updates since they'll probably be out in 2018. For example Metroid Prime 2 --> 3, Paper Mario TTYD --> Super Paper Mario, Mario Strikers --> Strikers charged, and Fire Emblem GC -- Fire Emblem Wii. So 2017 can still work. I guess Zelda U would come out 2016 and the remastered version or HD Twilight Princess will launch in 2017.
