The successor to the Graph extension will be Charts, and the scope is outlined in the project page. I'd encourage discussion on the talk page rather than on this task.

In T345962#10011310, @Sj wrote:

Since people implementing the fully working OWD embed were asked to pause it, could someone please add scoping when and how to support that to the Charts lineup?

I know we are still waiting on an answer about how to move forward with the OWID gadget (and I hope a decision will be shared soon), but I don't see the solution being to use Charts. Although the general concern of visualizing data for readers is the same, the OWID embeds are expertly curated experiences as compared to the editor-controlled visualizations that will be possible with charts. That said, people may of course still create charts using data from OWID that is available in Commons.