People in general are just so different.
If you for example drop by Tera's forums, they'll tell you Free to play MMOs is the devil, and they all can only run as Pay to win and that developers have no motivation to fix any bugs or add new content.
Meanwhile over here, at a Free to play MMO forum, there is no problems at all about this. Which I enjoy, since I think it is just silly to claim you gladly pay 15 bucks a month to play, but 15 bucks a month for cash shop items is unbearable.
What I mean is that it is an excellent plan to work on stuff that makes people want to keep playing, but that it is pretty hard to tell what that actually is. For someone it will be endgame grinding, for others crafting, for others dress ups, for others chatting.
Easiest is usually to read the forums and just act on that. Is there a 20 pages long thread about wishes for underwater areas and submarine suits? Well, guess it is what should be worked on next.