On certain problematic torrents with low peers, I tend to look around the peer list and re-connect manually to certain peers as it seems useful.
Some peers seem to work fine at a time but then suddenly get disconnected and quickly discarded from the peer list, which I can then fix usually via a manual DHT search to re-gain the IP/Port details and reconnecting manually, which then keeps the connection to that peer working for a while until this weird bug reappears, anywhere between hours to minutes later.

I don't know if this is actually a bug or just weird behaviour, but it would be nice to see this getting improved.
I have no idea what the default DHT refresh interval for existing transfers is, but it seems to be a bit low to help with such issues and it would be very useful for this and other reasons to be able to set it manually for single transfers and as a default value for all existing tranfers.

Also, I seem to remember that we were able a while ago to manually add peers into the list of single transfers to support this issue while it does not seem to be possible at this point. It would be very helpful to be able to do this again and possibly even be able to set a manual expiring time for certain peers so that they don't get randomly removed when all that is needed is a reconnect attempt.

Other clients sometimes don't seed very well and drop connection often, especially when they are trying to seed thousands of other torrents.

If you want to keep a peer from being auto-removed from the list, right-click it and open a properties window.  They don't disappear when there is a properties window open, ever.

That's good to know but that is more of an annoying workaround than a fix for this issue, which should be probably possible to achieve within the client.
The feature suggestions would be useful regardless of this issue.