Quetscher, your suggestion of a focus point is great. However, I’m not sure that I share your desired focus.
My dream instrument (and I believe that Daren’s as well) is a fine sounding, very responsive and yet lightweight; in a way, possibly the vintage Pro 36 (or your beloved Vibrandoneon) redesigned by Yamaha’s P37D engineers. For that matter, bending and everything that is unorthodox for a piano (and accordion) is probably out of the scope.
On the other hand, pitch bending and sound articulation modifying seem like strong requirements calling for a totally different approach. Therefore, there are possibly two very different dream instruments on the line, and we should not mix them.
Luckily, seems like Daren (which runs the practical aspect of this effort) is on my side.. 🙂