I like the feature to set a ratio at which ktorrent stops seeding. However, this may cause the torrent to die. If I am the only one seeding I don't want to stop seeding even if my ratio has been reached.
It would be nice if just below "Use limit" option an extra checkbox is added: "prevent torrent from suicide".
When checked, ktorrent should seed your torrent until both the ratio is reached and there is another seeder in the swarm (or a distributed copy exists).

Nice idea, except what if another seeder comes on which is also a KTorrent user with the same setting on? Or perhaps what would happen is that the other KTorrent seeder would never connect because he has the same setting enabled, so you would be stuck seeding alone forever unless a non-KTorrent user (or KT user without that setting) came on.

Really what is needed is a seed auto-rank system like Azureus has that ranks seed priority depending on seed:peer ratio. They say it's planned for the KDE4 version of KTorrent.