It would not be that hard, just look at open world games. They have towns with people and all that good stuff right? So why would this be any different? The fact they did not do it with XIII is because I think they wanted to hurry it out. The next FF title will most likely be able to have all the towns we are used to. Honestly if it does not then they are just crap and should give up all IP's so a developer with passion would continue them.
They have an engine now, so maximize it and use it.