I wonder how a good marketing team could change this. Or, it's rather a question of whether or not Ankama would be interested in that. The tight community aspect of the game has clearly fallen apart completely and no new blood is being brought into the game. If my memory serves right, even servers like Solar had more forum activity than Echo does now despite Solar having a lot less players than Echo does now.
I remember, during one of the dungeon rushers, I believe Count Harebourg, I saw .. seemingly tens of teams I had never heard of before, all taking up the dungeon rusher event. Having completed it, I never saw them again. Seems like many of the players turn up for very rare events and then bounce. Simply because the community isn't as active and fun to interact with. More community activities and events, as well as a solid marketing budget could still do wonders to the game, I reckon.