If it hasn't been said already...
One of the problems with subscriber retention is a mentor system that is lacking greatly. It makes it hard to bring ppl along in the game. Once there is a couple of lvls between players it becomes hard to game together. There are a lot of players that are left in the dark about the the in's and out's of the game that aren't covered in tutorials. Yes, RTFM does apply but mentorship makes it much easier and grows the community.
This is quoted for truth. Many, many people I grouped with all the time through Coruscant and Taris...and they played more than me and within a week, I couldn't run with them anymore.
Happened with the first guild I joined, too, in reverse--was a small (16 people after 3 weeks) very casual guild, and by mid-January, everyone was too spread out to run FPs.
Ironic, too, since this game has classes specifically based on rank and mentoring systems.