I think this game is amazing for the first 10-15 hours (varies depending on what you do I guess), then only "good" after that (atmosphere is doing a lot of the lifting to prevent it from being just "okay"). Like too many games, it is not one that grows with you (especially in reference to the enemies, more so the wildlife). Some ideas like crafting and taking over territory don't deliver on the promise they may have initially showed. I would still recommend it for everyone because how much I loved that first impression and it is still a pretty good game overall with a lot of cool things going on even if they don't all click together. However...
The UI is a pretty sharp blow because it is worse than many games which are not even aiming for the immersive first-person perspective (it might even be worse than Assassin's Creed with everything on and those games are very customizable with UI! AC1 was seemingly designed with no UI in mind, it was cool). Advertising treasure chests and showing enemies so clearly is counterproductive. The complete lack of survival elements is dreadful... Let's look at this honestly: patching yourself up, especially after a few tats, is essentially an unlimited auto-regen that activates with a button. It might even be more forgiving than most games given that some games won't let you regen until your safe (behind cover ideally) and in this game it is pretty easy to escape the enemy. There are virtually no rare resources and even a time-cost isn't involved thanks to how friendly the game is to traveling players (I believe I said something along the lines of "you never leave your backyard"). While I adore that it seems to limit quicksaves, that is another missed opportunity for some survival mechanics. Oh and here is one small complaint: This game is an ass for immediately showing me there is obviously a second island and the exact number of everything there will be to do in the game. Spoilering your own game with a checklist certainly doesn't make it more fun.
Though I pretty much summarized things broadly already, let me just leave some extra examples on how the game might begin to spoil: Killing your first shark with a boat is hilarious and exhilarating. I thought to myself "Ah yes, the Cthulhu technique". Once you realize you discovered an easy and safe way (as far as I'm concerned the only worthwhile way) to kill all sharks, it is a bummer. When you run into your first croc it will likely make you jump and that's awesome. Then you realize it is a QTE encounter which ends with the croc dying every time.
I agree that the story and characters seemed like a big missed opportunity. There is every indication that we would see character growth in a more subtle manner (and one more relevant to most of the game), but it is just not there. I guess it is sort of fan-wanky to complain about this, but add it to one those things that just didn't click despite having some good qualities. I don't necessarily hate the characters, but goddamn if the main character isn't awkward(plus HIS FUCKING HAIRCUT). He switches from so many emotions so quickly. Wuss to Rambo, worried about girlfriend to this party getting craaaazy (I get what they were going for...). It is enough to take me out of it. Overall I think some of the fantastic main missions makes up for any of this though.
I really would love to see this game get blown apart by modders like STALKER. I now remember why, beyond all its faults, I ultimately put down Far Cry 2 so shortly after I started playing it. Because STALKER with mods existed. In any case, I'm now at the stage, much like I was with Far Cry 2 years ago, where I'm thinking critically on how all the small and big ways this game could be better. Its moments like this where I want to be in the game industry, but then I realize what a terrible thing that would end up being.
One thing I lament about games is general is how poorly enemies react to sniper rifles (or perhaps explosive arrows, among other oddities found in gaming). You'd think that because the enemies live in a world where they know sniper rifles exist, developers would reflect that in how they react to their friends getting sniped or whatever. (Sorry for typos, dead tired)