I'm honesty sitting here trying to remember the last Ubisoft game I actually enjoyed. And I mean truly "couldn't put down" enjoyed. Some of the older Assassin's Creed games were fun, but the same endless gameplay loop was meh, even then.
I'd almost have to go back all the way to those original Rainbow Six games for something that felt (to me) fresh and innovative.
Far Cry 2 was the last game that brought something interesting to the mix. After that, the mechanics kept getting more dumbed down and turned into the Ubisoup we know today
Far Cry 3 was definitely a step back in some areas (fire!) but I think it was still a great game and pretty much perfected the Far Cry formula. Unfortunately after that game, Ubisoft just cannot move on
I would argue that the radio tower stuff bleeding in from Assassins Creed already messed up the formula that Far Cry 2 was building on. I do admit Far Cry 3 had some cool points, but overall it's where in my view the series took a step in the wrong direction.
Latter titles doubled down on making combat less meaningful, exploration just like any other Ubi title, and realistic animations, AI and physics thrown out the window in favor of cheap mechanics
Like, in Far Cry 2 enemies would try to heal their wounded or mercy kill them, in Far Cry 5 a baddie hover his hands above a body to revive their mate.
Heard on the radio towers, though I personally enjoyed some of the climbing as a break from the typical far cry chaos. At that point the dead horse had not yet been beaten, though, and it wasn't as much of an annoyance.
Cheaper / shallower mechanics is definitely also fair, and I agree Ubisoft sacrificed that depth for more realistic visual (common AAA loss). The npc ai in far cry 2 was a rare gem though.
I actually spent a lot of time playing with Far cry 2's map editor, and far cry 3 was a big step back there too.
I guess I just love the world, characters, and story of Far Cry 3.