I think there is a bunch of different things that can be said about the community. I would say that the greater majority is great. Something that I would consider would be that dungeons specifically are repeated and used and tossed content. They are easy to throw away because it's the same repeated instance over and over. Most people just want their tomes/gear/music and etc and to be done. There is a lack of open world community based content as well. Fates are a joke. One and done for a completion or there is zero reason to go back to them. They also severely basic in design and that makes those too awfully annoying.

To sum it up:
1) Lack of community based content.
2) Lack of proper incentivization.
3) Lack of open world connections.

Diadem/Eureka was an attempt to fix some of this. Pagos was a terrible variant.

That's not to say there aren't great parts, because there are... But there isn't much forced interaction which I think could help but it may not be marketable.