This could be very natural if designed well, and also doesn’t need to be an overlay, would work fine in the properties panel or as a popover. What I would like to see is the ability to craft everything about the note I’m interested in crafting. For example, see the humanization controls proposed here: https://www.steinberg.net/forums/viewtopic.php?p=1056236#p1056236
Would be nice to see the notation in context, bust open the properties panel/popover/overlay, set the CC curves, playback techniques, humanization, etc. and be done. Now I’m sculpting playback in Write mode very naturally instead of being forced to leave a notation context and deal with the piano roll. To RedtideMusic’s point, however, this implementation shouldn’t crowd the primary purpose of Write mode (writing), the interface should be subtle like other playback controls in Write mode (voice selection, playback offsets).
You could even go so far as to deal with phrase expression, also discussed in the humanization thread linked above, by selecting a range of notes and exposing shared properties like CC lanes. Now I can select a musical phrase, far more meaningful in a notation context, and adjust the CCs across the phrase… done, no need to completely change gears and kiss the score goodbye just to dial in arcs and swells. This type of expressive editing seems completely appropriate and natural in a score context, just keep it tucked away until desired.