Every new update or so we get a new dungeon. It's this other dimension where we get teleported, leave our big birds behind, and generally get locked out of whatever it was we would be doing with friends who aren't a part of our dungeon experience.
Meanwhile, there's all sorts of interesting places in the backgrounds of existing maps where we can't move, jump to, climb to, etc. There are vast distances visible but inaccessible. Huge chunks of the "map" display areas that are simply not part of our maps.
I would like future expansions of the game to have more places for us to explore. like the castle in Coerthus, or take a boat out on the beach, or climb further in the desert wastelands of Sagoli. So far, the only map expansions I can think of are Revenant's Toll and Housing.
But there's all sorts of "locked doors" and signs leading to no where, I would rather have a new town with some low and high level monsters outside than another dungeon to be honest.