I've never been a fan of these missions/quests. (I've only gotten far enough for WKR/Delve/Whatever)
I don't really see the point in focusing on finishing that mission line right now.
I think developer time could be better used with new bosses/monsters/areas/jobs/items/whatever else will keep all players around for a while longer. From what I've seen, few players are going to stick around or quit because of these missions, it has little impact over the community, I don't see the point in investing more time/money in it right now.