Overdubbing is fine, but how about overwriting notes like the Keystep 37 does?
Basically, while a sequence is playing, I want to be able to overwrite existing notes when I play new notes. It would also be nice to be able to easily remove notes that pass the playhead while pressing some button. This way, I can easily “mutate” an existing pattern when playing a monosynth just by playing new notes here or there, without having to re-record the entire pattern every time.