I disliked the ending,

I didn't like that they killed John at the end. I think the game should've ended when John went home to his family. I mean, that technically was the end of the story. Williamson and Dutch were dead, John helped the revolutionaries take back Mexico, those government agents didn't need him anymore, so the story should've ended when he got home, and then it would go into free-roam so you could do any side missions you skipped before. Even have those horse taming and cattle herding parts as side missions.

Then, they make RDR 2, picking up where the last game left off, where John is bonding with his son. All is going good, until Agent Ross resurfaces after so long and kills John, thus sending Jack to go out and avenge his father. Along the way he meets some people and they become a ragtag posse. Sort of like the first game, except they could add some new territories, add new features, and so on as the crew hunts down Ross.

I think they should've done it that way.

I'm torn with the ending. It's so great because it's touching but so horrible because John dies (and you have to play as Jack).

My favorite part and a good ending is when John is done with the Dutch mission in the northern mountains and gets to go see his wife and son. Whatever song starts playing, added with riding through the cold snowy mountains was the highlight of the game for me.

That's the point of this type of western. It's a more realistic version than most things would make it because it doesn't pretend there's happy endings.

I love this game, but I think that the ending could have been so much more.
I liked the idea of Jack going for revenge but I would have loved to have seen an actual final battle with Jack recruiting some help from some of the people John ran into along the way like the gun slinger from Mexico and a few of the others coming to help Jack in the final show down.
Now, that would have been an epic ending.

I thought Jack should have let him live to prove a point. Shoot the fish instead.

I liked the tragedy of it. The story and side missions of RDR have a lot of brutal stuff and I felt the ending just fit. You had this guy running from his past, trying to do right by his family and not have his son be like him, but in the end the sins of the past were just too much.He protected his family, but he failed to make his son a better man than him.

A similar arc is Jax from Sons of Anarchy(spoilers) He devotes a lot of effort to not being like his father or stepfather to finding a new way to run the club, But he just can't manage it so he hopes his son will be better. Jax is like Jack in this situation as they both fail to be better, but hopefully Jack's son if he has one can be better than him and John.

Only part I kind of had an issue with was Abigal dying off screen soon after John you didn't get a sense of John's sacrifice mattering because she only survived for a couple more minutes of screen time and Jack turned out just like John(also he kind of just sucks). John dying hit me hard and I wish it didn't have to happen, but he couldn't get out scott free, he had done too much. There was still a member of Dutch's gang left and Ross wasn't the type to leave loose ends