My most common workflow is to have a document open and selecting Save PDF to DEVONthink 3 via the macOS Print dialog.
Once the document is imported, I go to the info // Generic panel to enter in a Name for the document. It would be nice if this field would suggest names based on what I have entered into this field before. The Tags element does an excellent job of autocompleting tags. I would like to see similar functionality for the Name field.
I would also like to suggest that on this panel that the Tags element be moved up to above the Added date. After importing a document, I only change the Name and Tags elements. It would be nice to easily tab from Name to Tags without tabbing past the various date elements (Added Created, and Modified).
One other feature I would love to see is for DEVONthink to analyze the document I just imported via printing and suggest names and tags I have used for nearly identical documents in the past. This would save me a lot of time.