I do wonder if they'll consider patching in Wii remote. I know the Switch doesn't have the orange port, but it seems blutooth could take care of that with a newly designed sensor bar.
Gamecube controller compatibility seems like a no-brainer. But then again, putting analogs and a D-pad on the joycons in the first place seemed like a no-brainer to me. Part of the reason I'll hold off on buying a second set. I like the idea of a neon set but maybe I'll get some different functionality with something else and I don't need 'em for 4 player Zelda, obviously.
Forgot about the gyro. But at the same time, most games allow you to turn it off (ex. Splatoon). I'm hard pressed to see any games forcing the need for it.
And we still have yet to see HD rumble used in any meaningful capacity.
EDIT: in response to your edit, It's not like they'd necessarily have to keep selling WiiU Pro Controllers. Hell, it's not even functionality they'd have to advertise in any major way. But included support would certainly garner some good will, especially considering the ridiculous costs of additional controllers as is.
If developers create games with the assumption of gyro, having official accessories that don't support it could be messy. New Super Mario Bros. U IIRC was an example, where pro-support had to be patched in due to certain ledges in the game being rotatable via gyro.
I'm not saying directly that the Wii U pro controller shouldn't be compatible, I'm more saying the Wii U pro controller should have had gyro in the first place. But that since it didn't, deleting a variable/headache is understandable.
