Originally Posted by Sacred_Path
If you receive a new main quest pointer, you can be sure the nearest passage leading through the city will be blocked by debris, and you can be just as sure that the way to get there is via the nearest metro station. That could be become pretty stupid, if it wasn't, like I said, for FO3's atmosphere. Going through the metro or other underground locations is simply a hell of a ride.
Still, I think the FO's really open world is superior. Oh, also my path has never been blocked by radiation in FO3 (except for the fact that swimming can be bad if it takes too long).