I think a cool idea would be to have some sort of "High Priority" option for when you are downloading multiple torrents. What this will do is set more to all of your upload/download speeds to the torrent marked as "High Priority", until the download is completed.
I didn't see an option to do this within qBittorrent, so it should be included in the right click menu when you right click on a torrent.
To set "High Pirority" when having multiple torrents downloading
Re: To set "High Pirority" when having multiple torrents downloading
Options -> BitTorrent -> Queueing