I definitely agree with a lot of your points. I’m still not sure if this should be completely universal, meaning that it should purely show button presses (so FADC would be: cancel into MP + MK > cancel into forward motion, instead of an FADC “symbol”), or if it should be game specific. Because if you have to read ALL the button presses for a simple FADC, then you’re just like well why doesn’t it just say “FADC”. So it might complicate things more than simplify them. Different games will have different buttons anyways, but then again you’re still using the same “instrument” that is the arcade stick. I do appreciate all the feedback though. I’ll keep working on this and keep you guys updated :).
Here’s an example using the full notation for FADC. I also added a little notation for the number of frames for links and put the double motions on top of each other.
Or what if I add a note below the FADC inputs that just says FADC to make it simpler like this: