That's a very good question. I had plans to add major and minor pentatonic scales until it became clear that they way they are used, especially in rock and other blues based music is a subset of dorian modes. There's some real insight to be gained, especially with regards to harmony, or more practically, what chords you can play against a major or minor pentatonic. It's a lot more than one would think!
So, to answer your question, I'm not going to add pentatonic scales, but I do plan to record a video showing how GD can give you some really cool insight into how they work harmonically.
How about an option to overlay the pentatonic scales over other scales, similarly to the way you color the root notes but with a different color? You could use a similar idea to overlay root-third-fifth or other chords. I think this would be useful for those of us who are still trying to build muscle memory, but still present information in a way that minimizes "stuck thinking."
It's also Dorian and Phrygian without the 2 and 6. Plus you can use it in other keys, the A Pentatonic in the key of Bb is lydian, in G it's dorian, in C it's major, etc..
I agree with you. It's prevalent and is also one of the very first thing most guitar players learn. It definitely feels like it should be a prominent part of the UI and not just hidden away in some video.
So, to answer your question, I'm not going to add pentatonic scales, but I do plan to record a video showing how GD can give you some really cool insight into how they work harmonically.