I heavily use the "save to Dropbox" option in Gmail (using Chrome on macOS if that matters). I can choose a location and create new folders, which are amazing features; what I am missing is that I can save the file under a different name.
E.g., for invoices for my company, I always need to prefix invoices for the accountant. Currently, I have to switch from Gmail to Dropbox, browse for the file, and then rename it. Having a "save as ..." right inside the popup that opens up on the "save to Dropbox" would save me much time.