In the first part, the outsider was a mysterious and powerful otherworldly being. He shared with us a small part of his power, which allowed us to do incredible things. What he is capable of is even scary to imagine... Who is he? God? Demon? Or maybe both?

In the second part, we learned that he was once a human, which slightly spoiled the impression, but only a little.

And here we have Death of the Outsider...
Imagine the most boring and banal plot tool when it comes to the need to destroy someone over-powerful. Either a chosen one appears, or an artifact that can kill a God... This is the most predictable uncreative and boring development of all possible.
The expansion does a lot of negative things to the story's development.
Daud has no clear motivation for killing an outsider.
The writers played down the power and influence of the outsider in an extremely unconvincing way. And completely destroyed his image of a godlike being.
I was also surprised that it was possible to enter the void physically, although previously we had only entered it in dreams and visions.
And the outsider says that he can't see the future, although in the endings of both games he talked about the consequences of your decisions.

Seriously, for the integrity of the plot and lore of the series, this extension should not exist.
If the Arkane Studios ever starts working on the third part, I hope the "Death of the Outsider" will be completely ignored.