I don't think we need another dungeon similar to UT. We already have UT and "bug underwater tunnel dungeon" gets old quickly.
Plus if we want to have visitable locations on more continents (and I hope we will one day) that would require many and many UT-esque dungeons, which would increase the amount of loot and/or tedium of getting from one place to another.
I'd like to see a portal network connecting various continents. You could find and onld portal hub on Attnamese continent, and then you haev to do some short quests for each portal to open. Then, however, you can easily jump between continents.
This a) does not increase the amount of loot generated nor b) does it bring boring travelling through countless underwater dungeons from continent to contient. It does c) allow for quick and easy travel to mroe interesting locations once you clear the initial roadblock (the quest), thus d) giving space for locations on many continents, while allowing for pacing of the game (through the quests), so you can't skip to some high-loot end-game area easily, and without the need for many insignificant side-dungeons.