It depends on the game, not every game requires every button and you could just change the control configurations up when you need to. I fully played Zelda OOT with nothing more than a PSX type gamepad. It was a bitch at some parts (especially when it came to aiming the bow and arrow) and not the ideal way to play the game, but I did it.
I honestly wouldn't recommend it, but can't knock on them for trying.