Disclaimer, I'm level 44 and when I zoned in the mobs were mid 20s+. I'm a destro staff sorcerer, but only used AOE with the trash. With the bosses I ended up using resto staff and a combination of other things. I kind of did it on a lark, since no one was responding to a group request and I was kind of bored with CH questing.
I don't think I want that level of difficulty every single time I play, but it was quite refreshing. Highly recommend doing something like this for those of you who want a challenge and are complaining about the game being too easy. Sometimes you have to seek a challenge.