Not wanting to be that guy but part of the issue for new players is the skills, with extremely high buffs/debuffs and dps most new players continuously get 1-2 shotted in pvp so can do nothing, its tough for them to level and get ok gear +9/10 accesories etc then after being patient they hit PVP and bang they get stomped with 0 chance to effect pvp. This results in them getting abuse for going to BG's as they just give away kills with no chance of helping.
Also there has been little credit in the game for those that look after New players on the RG side Filomena has kept many many new players playing when they would have left, Kyoko also.
One of the issues for new players was that they see no one you run around an empty map and see no one at all. The DG added to Encocia was good for a while but it became irrelevant no one does it anymore so no one goes there.
There is also a lack of events, ball events in Encocia were good as new players could join in but bosses were ok to see people.
Lord Konton did a fantastic write up years ago on a whole range of great range of changes that would have made the game more newbie friendly, but nothing happened.
Also need to make the forums more friendly for players, too often you post something and get flamed or someone trys to change the subject, alot of people do not come on the forums for this reason. Admittedly this may have changed as I gave up on the forums a long time ago.
I am going to be honest I don't enjoy any quests they all get repetitive and dull.
I am not a fan of too many mobs in a PVP zone you want a zone that encourages PVP the Nemi Bowl with a boss in the middle was great, maybe some escort / destroy missions as well, anything to encourage pvp when it will be close enough. But you need to make things worth people pvp'ing over without the items dropping making one side too strong from continuously getting the drop.