This is a weird one, but I’d love to see a reimplementation of the sensor bar. The gyro controls haven’t cut it for me. I like how the Wii U game pad had the sensor bar built in to the bezel. The real engineering nightmare would be squeezing IR cameras into the top of the Joycon
Wireless Dock for dual screen gaming. Make it easier to port those ds, 3ds, and wii u games. I love having inventory and maps more readily accessible.