The personal story of 4 is superb and a really neat contrast. Games just simply don't explore relationships in such a realistic way. It's sublime. A Thief's End is one of the only times I've ever played a game where I started viewing the characters as actual people instead of graphics. The performances and dialogue are that good. For example:
https://www.youtube.com/watch?v=IwuPgc-CDtk
The direction is this scene is insane for a video game. The positioning and movement of Sam in the background. Elena, in disbelief looking over to Sully and his reaction is just utterly heartbreaking and feels incredibly real. You can glean so much from their personal history just from his apology.
While I don't think the series ever portrayed Nate as a purely 'good guy', I think it's pretty significant that a series of this stature would use it's swan song to break their protagonist down for 2/3 of the game in a couple different ways and then redeem him in a way that felt earned and not forced almost completely through contrition.
It's another step forward to me in the type of storytelling and character work we should demand out of games, especially ones of this type. Sorry there wasn't enough shoot bang to keep people from picking up their phones. This was always a series about the people and it was fitting that A Thief's End was the game that we got to conclude it.