I'm not too disappointed in the story for Forbidden West. The first had a great ending, tied everything together well, and essentially answered all the questions the world had set up. Following that was always going to be a challenge. I think they did a pretty good job on expanding the lore and moving forward from there. I don't think these games are built to be as narrative focused as God Of War, and you'd loose some of the freedom of exploration if you were to pivot toward something like that.
That said, I do have my criticisms as well. Like the first, I think FW is quite slow to get going. I also think the RPG-lite aspects of talking to people can be a blessing and a curse. For every time I enjoy a thorough conversation with somebody, there is instance where I feel frustrated to be in another static exchange with a huge dialogue tree. Even when this stuff is optional, I find it hard to skip over. There is a LOT of dialogue in these games. I applaud the effort, but can't help but wonder if there is a better way to implement it sometimes.
The locations are beautifully rendered. It's a world that is fun to explore. But... I expected a bit more of a dramatic difference for the 'Forbidden West'. Something more ravaged, more alien, more hostile. Wandering the ruins of the old world is nice but I think I was only really wowed by Las Vegas this time around. I was quite surprised by how little the red 'plague' seemed to factor into the game. I was anticipating some sections that were absolutely decimated. That could have made for some amazing visuals. It felt like I rarely even saw it.
My final criticism is my biggest. The machines are the biggest selling point for me. The designs and animations are fantastic, and the new additions are awesome and very welcome. After the first game introduced us to this bizarre mech-animal kingdom, I was excited to see how nuts this could get in a sequel, and it didn't really. A flying mount is great. I was sad it kind of ended there. Aloy should be riding Thunderjaws into ridiculous battles, summoning squads of Watchers for cover, taking down enormous beasts in multi-stage battles where huge hides need to be stripped down and removed to hit buried weak spots. I think this is the kind of progress that the series needs to make in order to step up and give us a next level experience. I did enjoy FW quite a lot, yet I'd say it felt iterative rather than an evolution.