Please make the note response faster when pressing a button with the horn, as well as make it possible to repeat the same note with less than a second or so in between. A lot of iconic brass/fanfare melodies require staccato on the same note. As it is, a lot of potential applications of the horn are impossible or have to be played very very slowly, even if one works around the major scale limitation.
Alternatively, at least change the behaviour when releasing and pressing the same note again to restart the note after the current default note length (thereby enabling at least moderately fast repeating of a note), instead of continuing the note if the time between release and re-press was not long enough.
tl;dr:
Make the horn more responsive, so we can actually play awesome stuff on it.
PS: Because people will surely argue that that would make the horn even more annoying, i would say the potential for trolling is big enough as it is with held notes, it can only get better