Maybe the very high and powerful of the players that retire (permanently) could do so in Athica.
At that time they could become trainers in their respective classes as to encourage and facilitate traffic.
The weigth could be that you have to pemanently retire that toon.
The outcome is that your toon becomes a part of Dalaya for the times to come.
For example, Xhas Monk 65 and puller extraordinaire decides to retire after a life of accomplishemnts in Dalaya, the Player permanently retires the toon and an NPC with the same name appears and becomes the class trainer there (since only one per class is needed, i would guess first come first served), another option would be to have class type merchants (ie spells or so).
That could make it the "perfect" city and alter the balance of the game, so not sure about it totally but i like the idea
It could also give high level NPC (ex-players) protectors to the city.
My 2 cps,