Truth be told, with how very overtly designed everything is, I feel trash mobs don't really add much to the whole experience.

Trash mobs are a great way to show that this is an actual "place" where people and monsters dwell, to make it look natural, but then you are led along unnaturally (and inevitably) placed quota trash packs that just stand around stupid as if they were waiting on the bus through corridors of invisible walls with often completely random gates to get to your standard perfect circle or square arena and... it just gets lost.

And if the experience is lost anyway, trash is nothing but annoyance at that point. The overworld suffers from similar issues with its very conveniently placed mobs that show absolutely no behavior that would indicate them being an actual part of the world. It's all very clinical.