It would make a huge difference for LIVE looping if there was a relative delete button on every track, like the relative play and stop buttons. MIDI mappable, of course. So whatever clip I just recorded could be deleted.
Another option would be a universal midi-mappable delete key, but then managing focus would be an issue. The relative button would make it nice and easy to understand.
Third might be midi-able undo. That might be best of all.
You decide.