Regarding the piano and where it fails ordered by difficulty to grasp, make:
I
⢠its keys widths and overall proportions are plainly wrong
⢠its shapes are limiting and restricting the player (see Chopin) from a fair access of touch\reach
â those two above being corrected would be enough
II
⢠lever vs parallelogram suspension
⢠Hickman's moded action (it is actually less difficult to make than Erard\Renner type of action)
III
⢠arc shaped keybed for ergonomic hand moves at both ends of range
⢠mirrored layout to comply with our natural symmetry of the hands (reduces learning by a factor of at least 4 especially for scales, chord inversions, arpeggios and counterpoint)
IV (mechanically very challenging)
⢠additional (but to me they are the most natural\trivial) expression features: vibrato, pitch bend per note\key
⢠dynamic volume control over the action (pedal)
⢠mute pedal (it is called sordino) with the purpose of representing the area of the palm on the pinky finger side touching the strings
V (electrical\electronic only, challenging for cost and application\harnessing all components mentioned below and so on)
⢠individual pickups for any set of string tuned to a pitch\note + PCB miltiplex boards, controllers
⢠piezo pickups under\on bridges
⢠sensor for any digital feature (parameter): velocity, vibrato\PB afterâtouch, pedals, stick\wheels
The other concepts with regards to Music notation are not so important although to me they are as the misunderstanding there throughout the centuries is equally as crucial.