The new Killer "the Hag", while not necessarily overpowered (except for the "Ruin" perk), is way more powerful than Ace, the Survivor introduced in the same DLC. Here's the lowdown.

Hag's perks:
Ruin-When a Survivor is repairing a Generator within the range of a Hex Totem, the Great Skill Checks do not boost progress, and Good Skill Checks remove progress.
Devour Hope-When a Survivor is rescued from a Hook within 24 meters from the Killer, the Hag earns a "Hope token" which grants her special powers.
The Third Seal-When a Survivor is struck by the Hag within range of a Totem, their Aura reading abilities are reduced. Upon striking a different Survivor within range of a Totem (does not have to be the one the first Survivor was near), the curse is removed from the first Survivor and transferred to other one.

Note that Totems that are destroyed will no longer activate these Perks whatsoever. Example, if a Totem near a Generator is destroyed, Ruin will not take effect, and Skill Checks will work as normal. Also, a Perk currently in effect will wear off immediately if the Totem that triggered it is destroyed, so if a Survivor was cursed by The Third Seal and the Totem that was near when they were attacked is destroyed, their Aura-reading abilities will return to normal.

Meanwhile, Ace:
Ace in the Hole: When searching a Chest, Ace has a chance of receiving an item with an Uncommon-level or lower Addon with it.
Up the Ante: The more Survivors that are alive, the higher the Luck of all of them.
Open-Handed: Increases Aura-reading ability.

Seriously, I don't even think the Hag is super OP or anything. All three of her Perks can be nullified if you target the Totems and cleanse them. I just think there's a serious power imbalance between these two here. Example: A team of Neas could probably get away from the Nurse, as their Perks counteract the Nurse's somewhat. Same thing for a team of Lauries vs. Michael. To an extent, they can use his Evil Within and Dying Light to their advantage with Sole Survivor and Object of Obsession. And that Decisive Strike thing is just awesome all-around.

With the Hag vs. Ace? Not so much.

I can see it now:

"So, what makes the Hag special?"

"Certain traps are set up in the Map. Her perks cause these traps to not only give her powers, but disrupt Survivors' essential abilities and cause unavoidable reflex tests to detriment them severely almost no matter what!"

"Wow, that's a very powerful Killer! Those Survivors will need to destroy those Hex Totems if they want out, that's for sure. What about Ace?"

"He's kind of lucky."

Anyone else feel the same?