Give other bonuses and items for Asmos, some good stuff and no time limited stuff. And like is it possible to give xp bonus for one faction only or something, I do believe that x1 rates are hurting the server overall, a lot of people on both sides probably quit before reaching 65.
Maybe is time to start working on character transfers to other faction from Ely to Asmo only and why not add an incentive to it like some gifts if you do make the change.
Block Elyos character creation for NEW accounts only (cause some old players might wanna create new char or delete one to remake it and find themselves blocked), and show in game that while going Asmo you are getting rewarded so that people know it from the game itself for people that wanna start Elyos blindly might get turn off if they see they can't create the character they want so reward them for choosing Asmo better.
Is it possible to modify the fortresses status ? Like giving Asmos 1 Fortress in each siege/zone permanently for now no need to fight for them like one in upper abyss and 1 in danaria so they only have to fight for the others, even if they can't they can still benefit a bit from one or maybe make it 2 I don't know.
I don't know what other ideas might be usefull, ofc this needs monitoring and to stop it when it balances out to not have the situation reversed again like before.