Here are some small adjustments which would make creating custom layouts way faster and fun :)
Scroll thru dropdown menus with arrow keys. This only works for changing channel number, not for semitone, scale, etc. Typing would also be very fast and accurate after clicking dropdown menus or sliders.
Use arrows to move selected "compose" elements
Change Fader direction (Vertical to Horizontal) Portrait mode (for some elements) Also animating lines becomes way more fun this way :)
Group / Edit "compose" elements Group similar buttons and elements so they can be edited and moved without having te reselect every time. Also group channel tune and style would be such a timesaver. Group scale? (but maybe this is very difficult )
Some bigger adjustments.
Save "Groups" (to library) So saving (and naming) these groups would be awesome. Maybe having a library to save grouped elements to.
Outside border workspace Below the Erae Pad border there still is space to compose different elements without having to put them on another layout. This could be the library space.
Change style of element directly in the work area (instead of clicking on VI IX or a key etc.)