When users preview pipelines with stages with complex types (say array of records) the UI gets the preview data back and displays as-is. Instead we should parse the schema in the complex type and render the fields.
Currently we render both schema and fields instead of just fields. This is misleading to users trying to verify their logic in preview.
Sample response for preview data
In the above sample response UI picks up the entire JSON under the arrayRec field and renders in UI. Instead, if the preview data is of complex type UI should pick up only the fields under the complex type.
As a Google CE while playing with the product, I stumbled into this story myself. Ideally, I'd like to see the data records richly described for debugging/preview. In an ideal world, I would like to see a field which is a record available as an expandable "tree" structure so that I can expand/collapse levels as needed.