I think it would be incredible to harness the power of Survey 123 cascading form technology in Web App Builder's application to edit an existing feature's related table.
This could be an extremely powerful integration for organizations who need to collect information on existing features and don't want new geometry.
Currently the only option out there (that's configurable and that I'm aware of) that allows you to edit/add related table data is the Polling Template. This app is great, but a bit cumbersome and not quite as powerful as Survey 123. I propose that there be an option to either embed the Survey 123 form into an iframe in the pane or make it a Widget itself.