The solution that I suggested, using a preset very short loop length, only requires one button press – in AP:LOOP playback mode, the Looper will terminate recording and start looping automatically when it reaches the end of the loop length.  It obviously doesn't allow the same flexibility in loop length that the Echoplex's SUS feature does, but if you're glitching for effect then an arbitrarily-short loop length ought to suit.  If you need a tempo-locked glitch, use TEMPO mode and set it for a very small note value.  Quantized dubbing would be nice – I've asked for that feature before, in fact – but I think it logically follows the features we're already getting, so I'm not too stressed about not having it already.