It would be great if you could assign custom tunings, and to do so without changing the sound samples used. These don't need to be linked together. If we could pick the tuning and sounds separately, it would give a lot more freedom. Having some Presets like Pentatonic, Major Scale, Harmonic minor, etc, and a Custom option to assign any Pitch (from a dropdown selection) to any of the Pads would be ideal.
Assigning Pitch to the Tilt gesture (like in the Tilt Lead preset) feels like a very natural fit, though the Pitch direction (from a 1/2 step above), isn't as useful as a 1/2 step below would be (chromatic approach tones, secondary dominants etc.). Being able to customize parameters more deeply affects how the instrument feels and plays. I thought this might be an option in Orbasynth, but unfortunately it isn't.
The Orba is such a fantastic little device with so much potential for music education and creation.