A good goal for product developers is “no screen needed”. With musical products especially, it’s primarily about what you hear, not what you see. Some things cross the line, and then having a screen is better.
I don’t see a real priority so far for a screen for this product. Mentioned in the video is including information on the tops of the keys for chords with notes outside the scale – for chromatic mediant motion and that sort of thing. Easy enough to see these other notes on an external screen or in documentation, for studying with your eyes when desired. Otherwise you use your ears, and learn the sound, the tensions, resolutions, and motion.
Aside : I just posted a video for a developer who set a “no screen rule”. The Wiggler is a product that has some similarity with Nopia with an arpeggiator mode and what i think is a custom scale option.
Another Aside : An aspect of Nopia that is available in other products is the single key press chord change and selection. For instance the Korg Keystage has 32 “chord sets” that can also be customized. I have a link to detailed documentation of those chord sets in this post. My opinion, the Keystage, might have been better, with fewer chord sets, if it had a “chord complexity knob” like on the Nopia. By the way no screen for these single key press chords on the Keystage either. The Keystage has other offsetting advantages though.
Another thought : An advanced feature that could show up in a final Nopia product, and something i would favor is a streamlined approach involved with key change within your music. There are several ways key change is approached musically, and this is often left on the periphery of these “chordal instruments”. It might be a nice improvement.