One thing I don't understand and it annoys the hell out of me. How can a game developer get universally maligned over a design decision in their last game and instead of learning from it, DO IT AGAIN? The most common criticism I've read about FC2 was the constant spawning/respawning, stealing the sense of accomplishment and believability.
It's not the same implementation. Far Cry 2 you could drive away and 2 seconds later everything would repop. People don't want that in Far Cry 3, they want a somewhat randommized system where the Outposts are retaken by the enemy in believable and reasonable periods. You're supposed to believe that there is a civil war going on after all. It also gives the player something to fight other than wildlife.
People hated the system in Far Cry 2 for different reasons, don't think for a moment people want that system in this game, it was an entirely different beast.