Best Mario Kart, best Donkey Kong game, great new ideas (Splatoon, Mario Maker). Nintendo always performs best when a system doesn't sell well.
To a degree, part of Switch's success was because of ports of great Wii U games.
Especially for Mario Maker, the Wii U Gamepad Touchscreen was better than the Switch Touchscreen, although the resolution was worse. The Switch Touchscreen lags behind too much.







