The expansion adds a new story act, two new class specializations, the Skovos region, and changes to the endgame. This is not a small DLC, but a full-fledged major expansion that will broaden the base game.
The average score on OpenCritic is 83/100, a decent result for an expansion, especially considering that this is not a new installment in the series. It is not a sensational level, but it is a fairly confident indicator ahead of release.
Reviewers highlighted the strong new campaign, which some are calling the best story in Diablo IV. They also praise the new classes, especially the Spiritborn, the improvements, a more structured endgame, and faster progression. Overall, the expansion makes the game feel more cohesive and fresh.
At the same time, there is also criticism. Reviewers note pacing issues in the middle of the story, complex systems such as the Horadric Cube, and activities that are not always successful. Some players may also fail to see a significant endgame update, as certain elements are perceived as an evolution of old ideas rather than a rework.
Overall, Lord of Hatred does not radically change Diablo IV, but it is receiving good scores and looks like a confident and substantial expansion for fans of the series.