So there's a tension between "being boring and usefully" and "being original at the cost of forcing your users to adapt".
Case in point : I had to explain a feature yesterday to a user, and it's complex and not trivial, and what basically saved my day was saying : "it works like in X".
Like games, wasd is movement, so every other game copied that. If you try to change, people are going to be mighty confused why the controls aren't "normal".
A wave of games that wanted you to play with the mouse and keyboard simultaneously made using the arrow keys impossible, unless you wanted to use the mouse with your left hand. If the auxiliary part of the keyboard had been to the left of the main part instead of the right, movement would most likely never have come off the arrow keys.
Sometimes though it is for the better. A lot of games in the 80s, especially on ZX Spectrum, etc, used QAOP for movement (QA vertical, OP horizontal) for some reason.
Of course the best is to have these configurable - both the Speccy games of yesteryear and modern games allow you to change the controls to your liking, so people who for some reason still prefer QAOP (is anyone still out there, i wonder) can still use that scheme in modern games.
QAOP requires two hands.
A common complaint from the French is that games have messed up movement. Why? The French keyboard looks like this:
A Z E R T
Q S D F
W X C
Even if you rely on scan codes, you're only guessing the button placement. They can be arbitrary, as long as user's key map matches.
Now you're down to arrows. They have an embedded meaning: directions! You can rely on them being placed in a way that makes sense to the user, even if it's not necessarily the standard WASD positions.
Even if you're worried about weird layouts, the biggest issue you'd see by far is keyboards that don't have arrow keys!
Even controllers assign buttons a meaning, rather than location.
> Even controllers assign buttons a meaning, rather than location.
Not really? There are arbitrary labels that change from controller to controller and the game displays whatever it thinks you have. Like keyboards.
But, again, if you're going to say "you can use the left part of the keyboard for directions", then you have different options, it's just probably safer to use wasd for QWERTY, qsdz for AZERTY, etc... rather than anything else.