Second comment, having read in more depth (really love the auto-layout detail!) - the spec doesn't seem to naturally support layering (which is useful in some multi-axis automatic cases) - any plans for composability?

We made an intentional decision to make it non-compositional for now, and we are using chart-type based approach to handle more expressive charts. (e.g., CDF charts)

But! We have a new project coming in to work on annotation machanism and interactivity to make it supporting presentation tasks.