Invasions are cool, but they are very limited and guild controlled. Limited slots, and limited time frame to play it. But its a great way to gather players together for some large scale multiplayer content. Another issue is that you can be kicked from this mode even if you queued for it early or spent your azoth to travel there to join the queue. Which is a big waste of time and resources.
Wars are also cool but its also more of a Guild vs Guild thing rather than any Faction thing. This is also very limited since its has a time window and doesnt happen often.
OPR is another mode for large scale multiplayer. It could use some better gameplay elements, but the main issue is that it takes so long to get people to join the queue.
Elite Chest Runs are rewarding, and a good way to gather players to work together. It has a daily timer of course. And this isnt something that is seen done all day long. Has its own social time frame here.
We need some large scale multiplayer content to do at more times of the day and night.
I wouldnt even mind some kind of cross server multiplayer version of OPR ,Wars and Invasions that happen 24/7 that any player can queue up for.
Because the game can get a little boring during the off hours on an individual server.
Some large scale Dynamic Event boss battles would also be something enjoyable around the clock to gather PvE players in the open world.