I have thought about his myself at an earlier point. The plan was to develop a system of forms across different Taekwondo styles, possibly even across arts. My idea was to establish a notation that is abstract enough so that every art / every style can interpret it individually.
I eventually gave up on such a notation because it's pretty much impossible to determine the right level of abstraction. I'll give an example.
A common technique in Taekwondo is
Bakat-Palmok-Bakat-Makki (Kukkiwon-Terminology, but the ITF-terminology is similar), a mid-section outward block using the outside of the lower arm, see the upper right picture in this form diagram). Basically the elements you have here are:
- direction of movement (outward)
depending on the style, this may be a horizontal or upward movement, the arms may be crossed or chambered or moved in a parallel axis
- weapon (outside of the lower arm)
depending on the style, this may be close to the wrist, close to the elbow, on the outside or on the top side of the arm
- type of movement (block)
depending on the style, this may be an offensive or defensive, pushing or breaking block
And that's just one technique.
Now who is to decide which level of abstraction is needed for which notation? As an example: I originally learned traditional Taekwondo forms in the 80s from a book (the "Choi bible") that didn't have many pictures and only vague descriptions (at least in the german translation). Explanations were often something like "Execute a kick in direction L". A kick? Gosh, we have a few of those in TKD, now which one will I use? Here, obviously the abstraction level was way to high.
On the other hand, a low level of abstraction means a very verbose text which is a nightmare for both author and reader (very error-prone and an awful signal-to-noise ratio).
I think, for a formal notation to be effective, you need an established common ground. A Grandmaster may just say something is a a Front kick and abbreviate it as FK, because his students will know his individual interpretation of the technique. But in an exchange with another master from another system, he will have to go into a lot more depth, the same technique will probably need at least two sentences of explanation.
Borrowing notations from non-martial arts (or from Sign Language notation) does not seem helpful to me, because martial arts techniques have purposes, not just movements, and these purposes are pretty unique to martial arts, I'm afraid. So, no, I don't think there is or ever will be such a notation that is powerful enough to give a common ground for many or all martial arts but still simple enough to actually be useable (and readable).