Given that Workshop integration isn't being worked on (to my knowledge) a replacement should be written for RTB.
Features that steam does not offer:
Server Prefs
Auto-admin, granting admin
IRC
Server options
Add-on hosting
I know a bit of torquescript, but I'm definitely not experienced enough to write most of this. (I could probably make the server prefs GUI, but i'm a stuff designer)
If you are interested, reply. If you are already working on a replacement, talk about it here, so we can rally together some developers and make it happen.
edit: We could also recycle the source. We don't have his backend server code but I assume it's not too complex