At the moment, especially after you have finished the campaign, the whole game feels like a character build-testing simulation. You basically never leave the end of time and run endless empowered monoliths (and some few arena runs) and the gameplay feels totally detached from the world of Eterra.
I loved the last patch where the new dungeon is not directly accessible from the end of time. Hopefully we will see more such changes that forces you to travel to a location on the map (please move the Arena out of the end of time to some lore/world appropriate location…).
Make cities/encampments feel more alive.
I would love more merchants to make the encampments feel more alive (this is important for the bigger cities). Split up the kind of wares the single merchant can have into a couple of different merchants. E.g. an Armor merchant, a weapons merchant and a misc. merchant. Another solution would be to have multiple merchants having wares from the same “random” table but not change their inventory as often.
More side quests. Maybe hidden behind faction walls so that they only become available if you have killed the kind of enemies/monsters that the npc hate (Grim Dawn does this well).
Less zone linearity:
Bigger zones this is especially needed in the early chapters the zone size introduced in the “Sands of Majasa” update was great.
Remove “immersion-breaking” QOL features.
Quality of life features are great but I would like that the immersion breaking ones to be removed.
Teleporting between waypoints when you are not standing on a waypoint (end of time) should not be allowed.
Remove Icons above merchants. There are so few merchants in the game that even someone as stupid as myself 
will quickly enough learn what npc to go to for trading/respecing etc.