I have a couple of plug in "hopes". I have no idea at all how a plug in is created, so I don't even know if these suggestions are possible...
1. The ability to save books in a Calibre Library by Series Or a sub folder in the author category by series.
2. After uploading to device - the metadata like summary and/or series chronology shows on the device.
3. Option to save epubs to library without the extra metadata/cover files.