Adding annotations to charts is critical for most of the stakeholders I've had and is extremely manual and a nightmare on dashboards - I don't think any tool solves this out of the box excellently. (i.e. allow users to easily annotate features of a chart)
Interesting. I also think a lot of functionalities, and annotations are definitely one of them, which are currently manual could implemented in much better ways. Fundamentally, charts really haven't changed much over the last half century (or more).