It's not that the dlc is harder per se, it's that builds which could handle endgame content fairly easily are getting one- and two-shot by the first bosses in the DLC. They clearly overturned the DLC, whether intentionally to pad the playtime or not, and most players will need to respec or grind for several levels to stand a chance. I'm still getting one-shot by certain attacks with 75 vigor and fairly heavy armor.

I also think the design of many of the boss fights are mechanically unfair, but that was the case in the base game too. I love these games, but the more they make the more they trend toward bosses with 10+ hit strings with many fake endings, deliberate delays, and unreadable animations, basically requiring dozens of attempts to learn the attacks before you have a prayer of properly responding to them all. I'm still going to complete this DLC but it's making me miss the more honest bosses of the older games in the series.