Via 1up.
 
Apparently the reason SE is reporting that FFXIII feels more linear and lacks town is due to technical reasons. At least that's the excuse they're throwing around. 
 
In an interview with Ultimania, Kitase and Toriyama claim that rendering towns in high definition is difficult.
 
I think this may also explain some other questionable factors in FFXIII, such as the choice to shift into a battle scene as opposed to fighting mobs in the open world ala FFXII. 
 
Personally, it sounds a bit like a cop-out to me. In my mind, I know they didn't want to take an extra year to get towns in the game and make everything look as good as it does now in FFXIII (keep in mind, this is arguably the best looking game to date), but I also feel like if they had taken an extra year, they could have gone that extra distance.  
 
I do think they underestimated how big of a part of the FF experience towns and exploration really is, though, and sacrificed it in order to get a product out faster. Which is not a good thing.