Objectively they have the fastest response time, assuming that there is no input lag from the adapter. (It won't have any most likely)
But optimal comes down to preference because of what people are used to.
Individual B might be more proficient with the Wii remote + Nunchuk, making the Gamecube controller not optimal for them.
Individual C might be fixated on using the Wii U controller Pro and will drill that controller into his hands. This will make this controller his most optimal.
Individual A might of never owned a gamecube controller and only have Wii remotes and the gamepad. This one will probably be optimal with the gamepad.
Individual D has 7 different colors of gamecube controllers and bought 4 mayflash adapters for Smash 4 in advance. I think its safe to say that his optimal controller is the
xbox controller.![Troll :troll: :troll:](/styles/default/xenforo/smilies/troll.png)
Gamecube controller.