I think it could be neat to leverage ligatures, i.e. preceding glyph could either affect the seed of the next or even make different "cursive" connecting swashes. Words could become pictures with individual "glyphs" blended together.
What surprised me is how often I have concurrently pressed two or more keys during typing, never occurred to me how frequently key press of the next key happens before the previous key was released. It could also be interesting signal perhaps.)
E: key press duration measurements doodle: https://codepen.io/myf/full/KwPwVWE