Until the Gamecube came out, I'd never played with anything but the N64 pad or computer controls. I loved my N64 and was a touch sceptical about the GC replacing it but, from the moment I picked up that controller, I was sold. It just felt so right.
So right that I played it till the rubber wore off the control stick. And then part of the plastic beneath.
The D-pad and C-stick were out of the way but not of reach. The main button was the big focus, just like it should be. From there, X and Y could be reached simply by rocking, perfect for racing games, and B was close but again, subtle enough that accidental use of the pointless break/block button didn't screw you over in racers and conventional fighters.
The triggers molded perfectly to the user's fingers and Z fit perfectly into the intuitive location for the index finger, without being so responsive that a loose grip would trigger it.
And, of course, it was a comfortable shape.
Many things were right about it. Things that are most definitely not about the Wii Remote/Nunchuck or the Xbox controllers (I've never tried the Wii U Pro).
It is not, however, irreplaceable. As the Dualshock 3 proved to me, other controllers can feel just as good as the GC one and, while an all round terrible shape and feel, the Xbox one has some of the very best in analogue sticks.
No, no other controller has a C-stick designed for smashing but remember, no other game needs it. You learnt to play Smash 64 without it and you had to make do without for the one player modes aswell, though. C-Smashes are not a make or break feature.
I love the GC controller as much as the next guy but I will be moving on, regardless of what replicas may surface.