I'm still not sure how I feel about the ending, particularly because something about the final couple of episodes feel like they just threw an ending together because they needed to end it.
So there are strange ideas like other teams around America, if not the world, but none of them help. Same with Thornhill being used as a last minute save, but not being a part of the final confrontation itself.
The Samaritan cop assassin guy (whatever his name is) felt like a throwaway character that went nowhere. A few episodes ago he goes to a hospital and gets a virus that is supposed to be used to "thin out the herd"... and that storyline just ends. They give him his own flashback to try to make him a bigger part of the show, but everything involving him felt a bit like the writers trying to find a way to end the arc at the last moment. I'm not sure what I'm supposed to feel when Shaw kills him, particularly when you have the Machine with Root's voice tell Shaw now to kill him while they were in the subway car.
This is a stupid nitpick that probably only bothered me, but I laughed at the blind devotion of the Samaritan agents. It reminded me of the dumb Uncharted moments where Drake is in the middle of an exploding building and rather than run away, all the brain dead AI enemies continue to shoot at Drake regardless of their own lives. Now maybe they had no idea a cruise missile was coming to blow them all up, and maybe they're supposed to be "ISIS-like" in their devotion to the cause so they don't care if they die, but it was just one of those things that felt silly to me. It didn't help that the actual sequence felt like a video game as well, because if you play any shooter, you have played the "sit here and defend the computer while it uploads" sequence at least once in your life (if you play The Division, then you've played it hundreds of times).
As for the ending itself, I'm... also not sure. The Machine can't beat Samaritan. It's something they keep bringing up... but she says that she can win because now there are actual stakes involved. In a way, it felt a bit anime, where the hero learns about the power of love and is suddenly able to overcome overwhelming odds in order to defeat the villain. I guess I'm fine with that? I'm not sure what I would have liked to see. Maybe a final confrontation between Root and the boy that represented Samaritan as they debated about what to do with humanity? I don't know.
I think generally I'm positive on the ending, but for me, I can't shake the feeling that it could have had a bigger impact for me.