Two options I would find useful (one requires added functionality in Deluge):
1. The ability to restrict torrent removal by save path. I use save paths in the following way - One path for torrents still downloading. Once download is complete, Deluge automatically moves the torrent to a second save path. Then, I then copy/process required files from the torrent before moving the torrent to a third save path for it to continue seeding. I want to be able to prevent torrents being removed before I have moved them to this third save path. I guess that I could set a label at the same time as moving, but this would require an additional manual operation.
2. I would very much like to be able to remove torrent based on how long it has been since the last download (leech) from that torrent. However, I'm aware that this information is not currently held in Deluge.