Eno would have been able to secede and pose a threat to the rest of Riombara, at least, if it took Jidington, Eylmon, and Irombro along with it...
Jidington, Eylmon and Irombro would cause a huge threat to a Grehk-based realm, even without Eno.
Might be fun for Lurians, but for the rest...? Players seem to be getting tired of how pointless it all seems. The whole continent is united against Luria Nova, and no progress can be made. How can you say politics are important if such a huge coalition is meaningless?
Clusters of cities will never yield if you attack the entire cluster at once and give them reason to unite. That's what clusters are. It's like mountains: an element of geography. You'll never win if you keep fighting uphill. That's why politics are important.
And I don't mean that your politics are wrong! There can be loads of good reasons to assemble a coalition in the way you did it. Maybe if there wasn't such a cluster of cities in Lurian lands you could have never assembled it, and Barca would have tried to establish themselves somewhere else that did not suit you.
