Okay, don't use that as a reason then. >_< It was just one example of one apparent impossibility.
I suppose if Rareware's off-board, not only does this save them from having a Z-button as a natural gun trigger (though there must've been other shooters on the N64 other than GoldenEye and Perfect Dark) but also from having Killer Instinct Gold become complicated with the C-buttons or stick, where a kick/punch and the strength of each one is very specific for creating combos.
Watching someone play Killer Instinct and pull off a long combo with the C-stick instead of buttons might be impressive, but would likely complicate an already tricky system, especially to veteran fans of the series.
There are other fighting games...at the time, I remember enjoying Dark Rift and Mace: The Dark Age. Those probably used C-buttons in similar ways.
I may be making a mountain out of a molehill, but I don't see how a C-stick replacing four C-buttons is okay when it's clear that if every button was replaced as a direction on a stick it really wouldn't work. I also didn't have issues with Ocarina Of Time and Majora's Mask on the GameCube, but I don't want the controller to force certain games to not be released or be overly tweaked just to fit a controller that could've simply had two more buttons.