TLS cipher suite configuration
It would be useful to be able to configure the allowed TLS cipher suites for both quassel-to-IRCd connections and for quassel-client to quassel-core connections.
This can be done through QSslConfiguration::setCiphers. I suspect the bulk of the work for this would be the UI plumbing.
An example of how this is done can be found in Mumble (another Qt app): https://github.com/mumble-voip/mumble
Mumble's murmurd just reads from a config file, though. They don't plumb it through to any kind of graphical UI.