Hi Chris,
I'm happy to answer.
1. We believe infographics are the future and we are focusing most of our development there to add more report functionalities to useful to our customers. However, we are always open to listen to our customer's feedback and you can submit your enhancement ideas here: https://community.esri.com/t5/arcgis-business-analyst-ideas/idb-p/arcgis-business-analyst-ideas
With regards to adding a legend in classic reports, the request also came from other customers so we are already tracking it internally as a future enhancement.
2. Yes, infographics have the same level of support for data enrichment using custom variables and interacting with tables. We actually have several examples you can take a look under the infographics gallery showing you how you can create reports with advanced tables.
For example, you can see the various tables on the second page of the Coronavirus Impact Planning template.
Here is another example called Disposable Income Profile from the infographics gallery we built using build infographics workflow:
I have attached this sample template below so you can explore how to create compelling tabular reports using infographics.
After extracting, you can import this sample templates (.brpt files) by going to Build Infographics > + Add template > Add template from file.
I hope this helps,
Fasil T.