I''m gonna go with Wii U.
Yes it was poorly executed but I had lots of fun sitting there with my mate in the same room playing multiplayer, on eon tv one on the gamepad and just sitting back and chatting.
They need to bring that back somehow with the next gen switch. Hell even if you connect two switches together.
They also need to bring back the features WiiU had. Easy to backup game files. That was a no brainer. Switch lacks OS content compared to even the Wii U.