Neogaf : Multiple reports of joycon issues in switch previews.

[SonytendoAmiibo]

sc94597 said:
Considering the ease of charging them, I think Nintendo is best off boosting the signal at the expense of joycon battery life. I hope they can access the joycon firmware.

Nintendo can't just change the Bluetooth signal with a firmware update. The hardware has already gone through FCC testing and is licensed to operate at the current signal strength.