Heh heh, can't blame the reviewers if what they saw were the betas. I am of the opinion that the MAG betas have hurt the game. That's why I was surprised the pre-order number is so high. May be it could be higher.
Will get the game in about an hour's time.
BTW, I am one of those who wander off frequently to learn the maps and kill snipers. Don't shoot me. I can't help it !
They are not segmented per se. You can leave your squad/objective and go join others if you want to. Your faction will usually be give 3-5 tasks to do at the same time. You're free to roam around at any point in time. You can also ride in vehicles to go to other parts of the map.