I do have one basic concern when it comes to any system of writing/reading music which is essentially intended to avoid learning standard notation; avoidance is not a great principle for learning.
In fact the learning curve for standard notation isn’t really that steep if you have a good teacher. Learning without a teacher, or with a bad teacher, will certainly make things more complicated, but the standard notation system is actually simpler than a lot of people think. It’s main problem is that it’s connected to a mystique. Your choice of representing the system with an arbitrary assortment of symbols is a case in point. Yes you have to learn a new visual language to read standard notation, but your system also requires some visual acclimation to get it. For instance, representing the black keys with skinny lines seems confusing to me. If you’re trying to represent the keyboard with your graphic style, why not just show the keyboard as it is? It wouldn’t take any more space than the way you’re doing it.
Also, if someone were to use this system to create their own written music, how would they go about it?
I think, if someone is intimidated by notation, that a sytem like the one you propose may actually work if it’s accompanied by notation, so that it acts as a bridge between the two. A diagramming system somewhere in between the actual instrument and the notation. So, rather than avoid learning notation, you could use your system to help people learn it.
Notation is based on lines and spaces which represent 7 letters of the alphabet in alphabetical order. If you start there, it’s really not so hard.