That would literally go against the core concept of the Joycons being symmetrical for duplicating controller purposes.
its still needed because some of us want a proper dpad for portable mode.
I get why its not a default option, but we do need it, or actually, maybe joycons with Dpads instead of analog sticks. for truely emulating the NES/SNES expirience. when shaying joycons.
anyway, I'd yet to get one myself (being a korean switch is coming out in december), but from borrowing a freinds, either the pro controler or split dual joy cons.