Yeah I agree.
It would probably be quite easy to set up using the same warpy2.js (from the groove~ helpfile and the fabled “bird finder” patch).
Can also just be a tie in with my suggestion for a better multichannel waveform display, especially since the slice point UI/UX is already in the warpy2.js file (though attached to stretching the buffer around.
Maybe a tweak on that would be using different “pointers” at the top to designate the start and end of a slice (if future segmentation objects give onset and offsets).