One thing I noticed with Piano is that it relies on the keyboard layout. As a Dvorak typist, I've often wondered if there's some way to do input handling better, such that applications which are more interested in the position of a key than its associated symbol (e.g. FPS games looking for "WASD") can just get the key at that position, instead of looking for a "W". Another gripe I've had with keyboard layout systems is that there's usually no way of indicating to the OS that US Dvorak is the natural layout of a keyboard, so instead of doing nothing when a "US" layout is selected, it translates it from US Dvorak to US, and does nothing when a US Dvorak layout is selected in software.

Added clarification:

There are at least three important things about keyboards in my view of things: the symbol or intent of the key, the "position" of the key in a set of cultural contexts (e.g. typewriter-style keyboards, left hand character movement controls, etc.), and the actual physical position (relative to other keys) and form/scale (relative to the world).

That's interesting. It could be neat to include key position as a field in the system keyboard events, along with the character, shift states, etc.

In fact, the keyboard scan code is basically position information :)

Key position it’s something I never thought about! Interesting idea, that should be a thing.