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
Contact customer service and ask for a repair. Nintendo got mass sued a couple years ago over the poor quality of the Joycons, and now has to repair drift for free even if the warranty period is up. I am not sure whether this applies to all parts of the world (I live n Germany), but I personally sent my Joycons to repair four times since buying the system (last one was in January) and always got a joke invoice for zero Euro from them. Only thing I had to actually pay for was postal service.
Even if they decline …asking doesn’t hurt and might be worth a shot.