I'm thinking of a few plots in my current in-house tooling which are slightly different than the standard charts we look at. For example a custom parallel coordinate chart that can use aggregations, categorical variables, etc.

This can be done by comparing experiments, then check the Hyper-Parameters tab, and select graph from the drop down at the top

So my question in general is pertaining to if I would need to get better at Javascript if I were to make those changes. My guess is yes as those changes seem to be at the web UI level. Does that make sense?

Long story short, yes 🙂 the web UI is obviously javascript, and to add features to it you need to code JS.
Do you have other ideas? Because I think it will be very cool to allow user to fully configure the dashbaord, I'm just not sure how that can be achieved without actually add features into the web app itself.