Good points. I haven't thought a lot about it, but I still don't see how this new system is radically easier to learn. Looks like I have to be concerned with notes partially on lines, an irregular staff, two notes occupying the same "space" on the staff, etc. Then there are clefs with numbers...now I have to remember what "number" octave I'm in. And for piano, you lose the white key/black key distinction, which is obvious with accidentals in traditional notation. (This is specific to piano, and maybe not terrible.) I just don't see any tremendous reduction in cognitive load.
I'm not sure what I think about this new system but the "black key = accidental" association is probably not very helpful to anybody playing on/after an intermediate level as there are cases where accidentals mean white keys (for example f flat or g double sharp). It might be helpful if you're a beginner though.
While we certainly run into Fbs or G##s, they are relatively rare. I don't think they undo the visual cue of seeing G# and knowing that's a black key. But you might be right. After all, if we're playing in the key of E, G#s are not notated other than in the key signature (and some other exceptions that don't really matter here). So yeah, maybe accidentals <-> black keys isn't such a big deal.
