i would definetly go with some hard content like having to do a very hard chain of quest to get a key to some new area or a dungeon with lots of dungeons in it with different bosses in every one of them, gear should be good for at least a year in my op. so players can look forward to get em, after the first expansion they should rise level cap and give endgame gear that last for a couple of years but make it in some way hard to get not with the drop rate, more like having to get different mats from different mobs or difficult quest or dungeon bosses to be able to craft those, that should help new people to let em be busy with that stuff.

They need to add NM's with background stories, so you can have some lore there not just kill the new guy, but something that makes you think you're doing something, in other games if you completed some quest chains, at the end the whole area looked different to you and the people who hadnt finished those couldnt see the difference and some of the new content wasnt unreachable for them until they completed that, in example could be like getting all the content done in the rescue of the city of Ala Mhigo can let you get in while other ppls that hasnt finished it cant get there, cant attend to defending events, etc.

I think this game its taking some of that by adding enemy company leaders on sight, like 14 companies you have to defeat to rescue different zones of the entire world, maybe im wrong but that sounds really good, so people will be looking forward to clear content just to get to those areas, friends will be helping each other to clear content and play together later on.

0.02