What should the DA4 gameplay 'hook' be?

Big open world games - assuming that is what DA4 will be - feature a lot of content.  Not all of that content is necessarily worthwhile or enjoyable to an individual player, but it is there to be experienced if they so desire.  Often, when a player is finished with the main story, they may be burned out on a game and think they have no reason to try again.  A 'hook' would be some small gameplay mechanic that keeps people coming back and engaging with the game.  Maybe it is monetised, maybe it isn't.  

Games that feature a hook often seem to have far better player retention than those that don't.  I saw a - joking - post on CDPRs forums a while back asking if anyone else had noticed that they'd added a 100+ hour fantasy RPG experience to Gwent.  I heard Fallout 4 allows base building.  DAI had this type of thing - in a way - with Skyhold customisation (although because items just appeared in chests randomly it may not have achieved the level of other games featuring this type of thing).

Acknowledging that we know almost nothing about who we'll be playing in DA4 or what they'll be doing, what kind of 'hook' should Bioware consider implementing?  What kind of mechanic would you be interested in seeing?

Implementation is the key, of course.  Using fishing as an example;


You can't just have an interaction prompt pop up by a river and an animation showing your character fishing.  You have to be able to buy - or make - a fishing rod.  Your companions need to chat idly while fishing - fortunately, banter is already a thing - and hopefully your character would be able to interject as well.  The game should keep track of how many fish you've caught vs companions and the respective weights.  Perhaps there are fishing contests in the villages, towns and cities of the map?  Anyway, I hate fishing - but hopefully the question is clear.

For myself - I think I'd like Home building, where I can buy or find in the world supplies with which to make my base feel like a home.  Design it, as well, so that each persons home featured a different layout.

Edit: Note - the options above are examples only, so if you want a mini-game that requires in-game items - it doesn't have to be a card game like Gwent - the example is just to give a point of reference.