I think the main site navigation bar at the top of the screen could be improved. My suggestion:
-> Expeditions (Dungeons)
-> Stories (Quests)
I think it currently is quite hard to find two of the main categories. "Activities" is an ambigous category term that isn't clear enough. Expeditions and Stories are important features that should have priority and shouldn't be hidden in the "Activities".
I think it also helps to make it clear that Expeditions are Dungeons and Stories are Quests, since those terms are the standard in other MMOs. This way new players don't get confused by new terms.
Outpost Rush can be removed, because it is only really relevant for max level characters. In my opinion it doesn't belong in the main navigation bar.
I personally had problems while using the navigation bar and I'm pretty sure I'm not the only one.