I think there can be different levels of completion. For example, you can do variant dungeon once, and get most of the story and you open the variant dungeon specific currency shop in Old Sharlayan. Clearing all 12 routes will be somewhat time consuming but you get an actually decent mount and rest of the story with it, and it's definitely locked behind a grind that a casual gamers can easily enjoy. Criterion is then for the midcore-hardcore crowd, and it's a bigger time investment with more rewards.

If we take Eureka (today) as an example, it's a considerable time investment JUST to get the basic story, and the time investment is basically all for naught as you've reached level 60, because there are really no rewards unless you plan on doing the relics, bunnies or BA. The lockboxes only drop anything worthwhile pretty rarely.

So I think they need to divorce the actual field content and the story it provides, at least a little bit. Kind of like you need to clear the Hildibrand questline to get to the relic weapon stuff, but if you for whatever reason don't want to do that, the Hildibrand questline itself will net you a minion and a mount, and depending on your humor, some fun times, and a trial to boot. So I feel like that's where they should guide the experience, without neglecting the actual field content of course.