When designing a notation, you're choosing what parts of a work you consider to be essential (notated) and non-essential (non-notated). That is itself an artistic choice. Everything you choose to not represent in the notation is something that you are letting future performers or cover artists choose for themselves.
The notation serves as sort of a negotiated dividing line between what the original artist wants to claim for themselves and consider a required part of "the work" versus what future artists are allowed to participate in.
Given that modular music is rarely played by anyone except the original author, I suspect that standardized notation isn't very important. All that really matters is each author having their own private shorthand so they can recreate what they care to recreate.