It's getting to the point where the touring musician is about the ONLY person using mono any more. Studio, home, and even a fair percentage of those touring pros now use stereo. I don't know if there are enough 'mono-gamists' left to be able to put pressure on the manufacturers to include non-phasey mono pianos as good as the main stereo ones in modern keyboards.

Most WS's suffer to similar degrees (Kurzweil are one of the few that make a point of building special mono pianos as good as the main one), so it's not just us arranger folk that suffer here...

But it needs addressing, one way or the other. It is frustrating to have SUCH a good piano sound so much worse because the manufacturers can't IMAGINE that what they make would EVER be played in mono (despite a 'mono out' jack on every last bloody one of them! )...

You want the problem to go away, start bitching at your dealers and reps and support forums. Or go stereo!