This is the same argument I always use to defend FC2. Only, in FC2, a big part of what made the emergent elements work so well was the synergy they had with the overarching goal of immersing the player in a hostile world, and trusting that they would find their own fun without being guided to it. There seems to be no such goal in FC3.
I think the goal in FC3 is largely the same, but as I said earlier, I also lament the removal of some of those elements from FC2 that made the world feel more dangerous. On the plus side they did put a lot more emphasis on unanticipated behavior with animals, which works very well.
Either way, I think the "find your own fun" element is still very much there, and the game leaves things open enough for it. The objectives are largely similar to each other - typically "go kill this person/these people" - but there are different ways to approach and accomplish them.
You can probably just use a silenced sniper rifle to complete almost every objective, but if you want to mix things up, there are some fun things you can do. Leading a bear into an enemy encampment as a distraction while you start a fire isn't something you have to do, but it's certainly amusing. You don't have to stick a piece of C4 on an alarm, make yourself known to the baddies, and then blow it up when someone goes to trigger it, but it's a hoot.
The constant, intrusive in-your-face feedback with player rewards and goals is an annoyance, but it's also something I've become almost oblivious to just because it's been so common in AAA games for years now. I almost don't even notice it anymore, but I do wish it wasn't there. Achievement culture is what it is.
My ideal FC3 would have changed/added some of the following. No idea how much of it is within the scope of mods:
- re-work the UI and allow the player to disable pop-ups
- re-introduce gun jamming, durability, and/or some analogue to the malaria mechanic; you should never feel too safe unless you are in an actual safe zone
- re-work some of the in-game economy, i.e. towers should no longer offer free weapons
- remove those annoying "mission zones" that automatically trigger when you get in the vicinity, and then can't back out from
- make night-time darker, and I'm not sure if the game already does this or not, but enemy visibility should also be reduced at night to add risk/reward to night missions and differentiate them
- enemies should carry more varied weaponry; I know Vaas is a hardass but surely he can outfit some of these guys with something that isn't an AK47
- more aggressive A.I. - if enemies notice a dead body, they should patrol the area more thoroughly and it should take them longer before they reset their behavior back to normal
Overall, though, I've been really enjoying the experience. Just the simple feeling of stalking prey - whether human or animal - with a bow while slinking through dense foliage is conveyed beautifully and still manages to be incredibly immersive even with all of the shit on the screen.
I've gone stealth in FC3 much more often than I did with FC2 (or even Crysis). And the fact that enemies can become alerted to a "presence" but still have no idea where you actually are or who's responsible means you can also do a lot of fun stuff with distractions and misdirections.