My rating is actually 3.5. It's a great expansion but I have a few criticisms.
The good: main story is great, the new machines are challenging and the map is designed well (more on that later). They also group different machines together, which make for intense battles. You have to be strategic. I played on Ultra Hard which made it very difficult, but not in a frustrating way. Aloy grows as a character. I actually like her character growth. She goes from being a socially awkward (in many situations), yet empathetic outcast to a battle-hardened warrior with the weight of the world on her shoulders. That does change you to become dismissive, rude and temperamental. But she changed towards the end of the main game and grew further here. Seyka was a mirror that reflected back on her. Her character was good as well. Finally, the graphics - stunning. Also, the main villain is played by Sam Witwer...he's incredible.
The bad: the story is too short. There isn't enough side content. There should have been at least 3 more side quests. Final battle variety. While it was impressive, challenging and hard, they could have added some more variety there. Amazing but could have had more. Finally, as amazing as Sam Witwer is, they don't utilise him enough. I'm also marking down because Sylens isn't in the DLC enough. I know it's illogical but I stand by it. RIP Lance Reddick. You made Sylens into such an engaging character.
This is a great addition. People are saying it's woke...I don't like woke stuff. This isn't woke. Analyse it properly. Aloy is a character that is growing well. There were subtle clues that Aloy was a lesbian since Zero Dawn. More obvious in Forbidden West. There's no man-bashing. There's female empowerment, in the sense that the leads are female, but that's it. The game developers did an excellent job. I applaud them.