Maybe more external live chat or communication ?
On the face of it this would encourage people off-site, but people tend to stumble into UT rooms in the IRC and other chat systems, at which point you snag them
Perhaps we can use something like Twitch or google streaming as a focal point for matches and even editing sessions etc.
I am not sure but maybe a live youtube link would embed here.
How about a cinema room ?
I use a site that synchronises video streams so people can all watch from the same point wherever they are, with an integrated chat room.https://synchtu.be
It supports a few different video sites and also direct links to files.
You can make as many channels as you like so create themed viewing rooms.
eg. I made rooms for a few collections and serieshttps://synchtu.be/r/Frankie_DayZ
(gamer zombie series)https://synchtu.be/r/Star_Trek_Phase_2_New_Voyages
(unofficial sequel to the original Star Trek, with guest original cast)https://synchtu.be/r/The_Laboratory
(scifi, old B&W B-movies, old drug "information" films, Atomic bomb experiments, and google deep dream vids)https://synchtu.be/r/15_Percent_Extra
(Full music concerts documentaries and vids)
We could have a room that we change regularly or add more to.
Currently my music room has a very classical and old rock vibe, and is family-safe
A room can be moderated and set to stay or disappear if no one is in.
People can vote for the vids they want next, and mods can simply pick a new vid to start.