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.