Let me start this off by saying I absolutely love Arthur Morgan. When the trailers first started coming out showing him off, I thought I was going to really dislike him compared to John Marston. But as I played the game, the more attached I became to Arthur. He's funnier than John, and generally has a more positive outlook even though you can totally make him a murdering psychopath if you want. I also appreciated that he didn't really have any motivations for the first four chapters other than just making money for the gang and being loyal to Dutch. I kinda like that "blank slate" approach where you get to shape the character a bit instead of being set in stone, like John's motivation to get his family back in RDR.
The tuberculosis diagnosis hit me pretty hard even though it was easy to tell he was getting sick. Arthur starts coughing sometimes in dialogue back in chapter 3 even, and it keeps getting worse. I had a feeling Arthur was going to die in this game since for one, they did it with RDR, and two, Arthur is never mentioned once in RDR so I figured something would happen to him rather than him just moving on somehow. They did a good job developing Arthur's character after he knows he's going to die. I like how he turns into a man trying to help the people he cares about. Always made me sad when he'd have a coughing fit during/after missions. The first time it really, really got to me was the cutscene where he talks to the nun outside the train station. He tells her "I'm scared, Sister." The shakiness in his voice, the sickly complexion, his gaunt eyes. Tears were shed. Very few games have done a better job at making me get invested in, care about, and feel a strong sense of emotion regarding a character. All that aside, it was very cool to see just exactly how John ended up owning Beecher's Hope, and the epilogue gave us more Sadie who was absolutely my favorite character in the game besides Arthur. I almost thought we'd be playing as her in the epilogue instead of John, but he makes more sense.
There's a screenshot I took right at the end of the game, always tugs on the heartstrings a little bit to see that.
P.S. Fuck Micah Bell.