With this feature all of our dozens of controllers from the Wii and Wii U era would be working on the switch. So on parties with a lot of people it's easier to get enough controllers to work. It's also much cheaper to reuse the controllers that you already bought, instead of buying new controllers to each new console.
This was asked before already.
The simple answer is that this is way too advanced and takes too much time for what it is worth and Atmosphere is not at the stage where it can focus on such optional features.
I think if I did something this frivolous before emunand the people following this project would lynch me.
Ask another developer, or else poke me about it in a year or two.
For what it's worth, the GBros adapter already does exactly what you're asking for (excluding Wii U Pro Controllers, which do not send data over their Mini-USB ports).
Oh thank you very much! That's a very good alternative.
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I think if I did something this frivolous before emunand the people following this project would lynch me.
Ask another developer, or else poke me about it in a year or two.