Experienced players read music in a way that overcomes some of the limitations that form the assumptions that are behind these alternative notation systems. Instead of looking at a measure as a collection of individual notes that must be perceived, interpreted and executed in sequence, they take it in as a chunk. (I imagine reading code must be similar.) This is why the density of traditional notation isn’t intimidating - after a while it can be read as a whole.
Whether a system like this could be a pedagogical bridge to formal notation remains to be seen. I’ve encountered such bridging systems before. I’m an admitted skeptic because my orientation to this is that if you want to learn a thing, just start learning the thing. The struggle, within limits, is known to enhance learning.
So, what I've learned is not to completely discard v1. Instead, it's better to refactor or rebuild only the parts that pose issues, even though it may not be as sexy or exciting as starting v2 from scratch.
In practice, I would begin by cloning v1 and deploying it to a development environment to start tweaking it. I would also ensure to implement numerous automated tests to safeguard against any potential issues caused by refactoring. Of course, if you can keep using the same database that's even better as you can test refactored features with real customer data and even run both builds in parallel to spot any differences.