Hi there,
Lots of ideas today. One more about keywords: It would be a good idea to look into Natural Language Processing for the automatic generation of suggested keywords based on the content of the citation. Diigo already has that feature, and Evernote works in a similar way for the classification of a note in a Notebook. In Citavi's case, it would probably imply parsing existing keywords to see if they are matched in the text, and adding any additional location name, person name or more broadly capitalized word from within the quoted text. It would be a great time saver!
Thanks again
Francesco