It sounds great in theory but it would hinder a pianist. Pianists play on whatever is available to them especially during performances. Practicing on a modified piano vs a standard will impact their accuracy and performance for they normally do not get to rehearse on the recital piano. So the spacing of the keys would throw them off immensely because of the muscle memory that they built up on the smaller keyboard. I doubt anyone would want to drag their modified piano everywhere with them. xD