Here's a blue poster on why we have trash in the dungeons, which can be a pain in the butt!

"Trash" mobs do serve a purpose in dungeons though and while they may not be your favorite part of the dungeon, we try and keep a good balance of it versus the rewards of the particular dungeon.

Shattered Halls may have a fair amount of trash, but I believe it can drop up to five badges of justice which is the most you can get from a heroic dungeon so it makes sense for it to be a challenge to get through.