Like I have said in other threads people need a reason to join the line. If the line had a element to it which allowed players to feel a benefit from, such buffs, spawn points etc... I would like to see the officers name list and a join on them button. make the line officer a spawn point or spawn nearby point with a arrow to join them. The buffs from the different types of staff classes(musicians, banners, surgeons, etc) when implemented will also aid in this.
Oh wait until CAV hits the field, omg the chaos will be enormous. I just hope they make the horses run off the map after dismount or death. Horses will be everywhere, like row boats in naval. It will be delightful if chaos is you thing otherwise pray for the Admin Controlled Line Battle servers.