I am really enjoying using Paperpile. One feature I would like to see is providing full citation information when you click on or hover over an inline citation in Google Docs. This would be very helpful when using numbered citations.
Our optional sidebar add-on to accomplish most of this. The references (author and year) will show up in the sidebar when you place the cursor at a citation. It can also unformat all your citations so they become the blue placeholders again.
You can get it here.