So, I finally beat the game... some updated impressions:
On PS4, the last quarter of the game was becoming just painful to go through. Except for the main quest, I generally had to reload the game every 10-15 minutes either because of a glitch ruining a mission (it's hard to be stealthy when guards can see through walls, for instance) or because of a very serious bug (car becoming undrivable, menu failing to load, when it's not a straight blue screen -> exit game).
It seems as though the first... third of the game is quite playable and doesn't seem to be bugging too much, but the more you progress into the game, the more the game is falling apart. When I reached the ending, the game itself was agonizing. Time I put it to rest.
Not really the 8/10 I gave first. A shame because I did enjoy the story and its writing.