A RealTrack doesn't have a VSTi, it's designed to play audio. The underlying midi is for display on a RealTrack track. What you're now describing is simply a midi track that's editable in Tracks View and adding Partial Regeneration to midi. Which neither doesn't currently exist. So, yes, it's a wishlist item.
Editing underlying midi doesn't affect the RealTrack but editing or regenerating the RealTrack affects and changes the underlying midi simultaneously to match the new audio. The midi is there so users can see notation, tab if applicable, the Piano Roll view, The big Piano, the Guitar Guitar Window and users can use the midi like you have described.
Because of all of those above applications as well as underlying midi on a RealTrack has been a feature in BIAB since at least 2014, likely years longer, I'm not proposing anything. This is not a new proposal but a BIAB long-time major feature. It exists now. Not a workaround. It's not unstable, broken, complex, or hidden. It's a Rock Solid Mainstream Feature that's intermingled with about 20 other features.
< P.S. Some moons ago in a public conversation you stated in fairly plain language that if a function is present, you don't care much about the workflow. I have this feeling that it's a continuation of that conversation. >
Not really, but it's as true today as it was back then if that's what I actually said. It's true because when BIAB has a feature, I accept and learn PGM's design and functionality and use it. Simple and efficient and lots of fun.