You gave me a good idea for a RP. Despite that, yes, Dwilight and BT are doomed. At least in Angmar we can take a region while another is taken. The circle of (un)life.
Dwilight I think may still be salvageable, though the mass invasions Luria's had of late don't seem to reflect any appreciable drop in active player count suggesting there are unintended consequences in the underlying rogue spawn mechanics. We have the noble density of Westgard and the Adventurer density of Swordfell do if Luria can't stand against the hordes I don't think there's much hope for anyone else.
Admittedly we're too physically big and our long-planned realm split may change the economics of dealing with the hordes so they become more of a nuisance than an existential threat.
Beluaterra though feels like a lost cause unless we either give up much of our history and merge realms permanently in one small area, or else do something radically different with what the Devs have gifted us. I'm happy to try the radically different and anyone who wants to know what that might look like can contact me IG
