I really enjoy dungeon content, fractal content, etc. They have a lot to offer, gameplay-wise, story-wise, and setting-wise.
On the rare (rare) occasion where I find a group to run some core dungeon, said group always wants to speed-run it and skip everything. If we die a few times, people leave the party because they're used to steamrolling everything on the first try. If something isn't immediately obvious, no one wants to try to figure out a way to do it.
Fine. There's nothing wrong with speed-running, or wanting to do something quickly and efficiently, farming, etc. (I do it all the time!) There's something wrong, though, when it's the only way one can experience that content. You have developers spending thousands of man-hours creating content, dialogue, thinking of boss-mechanics, etc., just for all of that content to be relegated to a place where one can't actually experience it, even if they actively want to. I would love to be able to pick some dungeon, enter it, and spend a couple of hours (or however long) smashing my way through it, figuring things out, learning the bosses, etc.
I remember that a lot of the design of this game revolved around characters being self-contained units (everyone can heal, dodge, etc. There are lots of instances, personal stories, etc.). I think the ability to run dungeons, fractals, and other things would give players a ton of extra content to play with.