Not using a Gamecube shell defeats the entire purpose of it.
It won't happen. It's a pipe dream and the only thing you'd expect is a subpar Third Party Controller.
You still wouldn't be able to fit a conventional battery and all the other things needed for a wireless controller due to the dimensions of the GC Controller. Take a look at the bulge on the back of a GC controller compared to a Pro Controller. They'd need to change the design, which defeats the purpose of a GC Wii U Controller.
Though it is true that the GC molds better and gives more comfort room for the rest of your fingers, it's nothing that can't really be remedied through a few game sessions. Give yourself some time and you'll transition fine.
Hell if you compare buttons, the Pro Controller is Sanwa Denshi tier compared to other conventional controllers. Shorthopping and inputting commands is much easier and much more fluid in comparison. Analog placements are also superior due to ease of access of the C-Stick.
It might just be personal preference but honestly the Pro Controller is here to stay and it shouldn't have to be a factor as to whether or not you play the game. The faster we adapt, the better so that we don't have to hear continuous whining and complaints for a controller that worked best in a previous iteration of a franchise, one that plays significantly different.
Not calling you out, just putting my stance out there. What do you think of the Pro Controller anyway? I find it to be just fine and it works great. You can fast fall, short hop, crouch cancel, wavedash, anything due to how the buttons are.
