So it's been 2 years; which Wii U game makes the best use of the Gamepad?

[Areal-Llort]

Pikmin 3
Wonderful 101
Rayman Legends
Wii Party U - Several minigames, such as the Baseball machine and Foosball table.
Nintendoland - Specifically, the Luigi Mansion and Animal Crossing mini-games.
Art Studio (eShop)