I totally agree on this one!
In fact, I was about to mention the same thing when I was writing some other suggestions, but then I forgot.
I also had the MPC in mind. Here’s a video where the guy uses this in a track.
But the whole loop recording on Renoise should get improved, IMO. And the “hold-note recording” feature could be just a part of quantize recording, which was suggested already. (possibly with different quantize for each track)
Anyway, for now, editstep in pattern follow would be nice as well.