Even hub worlds are more streamlined, and the narrative is given greater focus. Most of the time, combat portions of missions will take you away from the hub world, and transfer you back once you've wiped out all the get or mercenaries or whatever. I don't want to give too much up front before completing and reviewing the game, but his aspect of hub world and off shoot keeps the player from ever getting lost. While I haven't had any first hand experience with Final Fantasy XIII I have a feeling that experience will be shaking hands with much of what Mass Effect 2 does.
This finely funneled narrative is really what will make all the difference in RPGs in the future. What is the evolution of the RPG? How much of an RPG do you really enjoy? Does anyone really love random encounters? How about an over-world with no real direction? Do you like grinding so you can beat a boss that's standing between you and the end of a dungeon, the continuation of the narrative? Personally, I only really enjoy the story, the narrative, the world, the characters, and those things don't make 20 spare hours of grinding and leveling worthwhile to me, especially when other genres are getting fully competent at telling stories within their gameplay parameters.
I'm nearly done with Mass Effect 2 and a review will be up soon. Suffice it to say, I'm thoroughly enjoying the experience thus far and I will purchase any amount of DLC that is released. Much like Ubisoft with Assassin's Creed II, I just can't help but get enough of the world Bioware has created, or enough of the gameplay either.