I go to a forsworn camp(Hag's End), kill pretty much everything easily up until a briarheart, the briarheart kills me in three quick swings in I assume a dual wield power attack with dual axes.
That means they're doing roughly 300 damage before armor is factored in, with one handed weapons. I can take more hits from a Draugr Death Overlord with a 2 handed ebony weapon than I can from this briarheart. This thing is hands down the most powerful creature in the game I've encountered so far, it's not even a contest.
I'd be like "okay" if this was Alduin or something, but it's just a standard leveled enemy type wielding some of the lowest level weapons in the game. If it's not a bug it's just plain stupid.