I also quite enjoyed
Far Cry 3, especially the mission in that video. What I loved most about that mission was the fact that Jason actually had fun in the game. If I was given a flamethrower and was told to go burn down a pot field, I'd probably be having the same reactions that he did in that video. It's a rare treat to see a video game protagonist actually enjoy themselves in the game.
Anyways I played a couple of hours of this the other night.
Personally I really enjoyed it, but I can at least understand why people are upset about this. I will say that if you were on the fence about it after last year's roof top chase sequence trailer and hearing about the skill tree upgrades, the game got rid of both. The amount of customization in this game is absolutely crazy, both in the options menu and in the difficulty. Right now Square Enix might be one of my favorite PC developers because they consistently put out quality PC ports. The difficulty customization comes from being able to disable certain tools, so for instance you could disable all your arrows and just have to try and stealth your way without using things like rope arrows or water arrows. These give you more points and add you to a leader board but I think this is one of those instances where a leader board is actually applicable. Not only that but it really increases the replayability of the game as you can try and set up challenges for yourself.
The story so far has been a little weak and the humourous Garrett from the previous games has largely been placed, but as far as straight up stealth this game is really good. It also has some of the best shadow and lighting effects plus some really impressive particles, although the wood textures are a little weak, but if they allow modding I'm sure a texture pack will be one of the first fixes.
I'd recommend it, but I'd also say read some reviews by reviewers whose personal biases in some way reflect your own. The reviews have already been pretty divided on this game, but it'd really piss me off if this game failed because of its Metacritic review score.