Finished it this morning at about 4, wow.
Honestly, I have a little disappointment as I feel like the pacing is decently stunted in comparison to both Uncharted 2 and TLoU. Just going from a fresh memory of the game, there are either too many cutscenes or they are too long a duration. It almost felt like too much of Sam and Drake's relationship was getting waited on for cutscenes. I think A Thief's End isn't as good or as exciting as UC2 and TLoU, but it still has a ton to offer in terms of gameplay. The new gunplay mechanics in particular are absolutely thumping and intense, and the rope swinging was built simply enough that it doesn't feel like a new mechanic for the sake of it.
I think that replaying the previous games in the forms of the Collection may have actually hurt UC4 for me, at least in terms of singleplayer. The mild sluggishness of Nate's movement is more prominent and harder to control at 30 fps, something I had forgotten after playing the previous games at 60 fps. But you get used to that, and obviously enough the game is an absolute monster with the visuals.
And my final complaint were the antagonists, all of them. ND seems to enjoy using PMCs for standard enemies, which is fine, but when it's the fourth game in the series it feels a hint stale. The main antagonists were certainly interesting, but didn't feel as imposing, dangerous, or even as cool as the previous games' antagonists, even worse so in comparison to TLoU.
Overall great game, I'd probably rank it somewhere in the 8-9 range. Going to go for the crushing runthrough next, I don't think it'll be too difficult.
Edit: Also, the changes in fist-fighting were not necessary, and I preferred them in Uncharted 3.