When adding tracks, it would be highly useful to set up a track with the correct ‘note mode’ by default. E. g.:
The Red Zep’lin drumkit (and other stalwart percussive Ardour-friendly, “1-shot” instruments) could default to ‘percussive’ ‘note mode’ without having to separately set it each time one uses this instrument.
Even when adding non-familiar (to Ardour) drum-ish instruments a check box (in the Add Track/… dialog box) could help… Ticking a box (for percussive ‘note mode’) at that point would streamline the whole process of working with percussive notes.