The only real deficiency of the GC layout is that B+X and B+Y are hard to hit simultaneously, as are any 3-button combos that use B. In practice, though, opposing pairs are also awkward to hit with a diamond layout (though not as awkward as B+X/Y on the GC) and most games will try to avoid that anyway (which can translate easily to the GC controller), so that really just leaves trios as the problem (and that's
really
niche).
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