I like it, it's a great idea, at least in theory.

I did something similar to the 'practice mode' some years ago, just for myself, did not publish it. I used the The Synthesis ToolKit (STK) C++ library for the guitar sounds.

In the end, I didn't use it all that much, but I still believe in the idea. Maybe it's just hard to find the best expression/execution.

One idea that comes to mind is to highlight or find the different voicings/aliases and octaves for a given note, since most notes on guitar have at least 3-4 or four equivalents.

Another idea would be to color code the notes on the fretboard. Again, it's been tried before, but maybe there's a reasonably good way to make it stick into visual memory.