An interesting look back at when WoW: Warlords of Draenor came out, was that Heroic Dungeons (kind of like our Expert) were capped behind reaching a silver or higher rank in a solo trial challenge of sorts. You'd go to the Proving Ground (kind of like Hall of the Novice) but with mobs you had to interrupt, sometimes have particular kill orders in, dodge mechanics - everything that a real dungeon would have more or less). If you couldn't get silver, you were locked from the content. I don't know if it would work here. But boy, I sure knew people in WoW who literally couldn't do silver to save their lives and had others do it for them. But WoW classes are far more varied and generally broken than what XIV has, period.

Hard to say. Putting a requirement in front of people may just make them quit. The capable players will go through it. But it's that middle-ground that's tricky to get. But agreed, some kind of higher difficulty "Hall of the Expert" or a Primal simulation or something would at least help in assisting players with harder mechanics than in dungeons. Create a reward for doing it too and that is at least one method of incentive. That or some awesome solo-challenges would be great.