Regardless of your opinion on Final Fantasy XIII most will agree that the linear design of the game was very restrictive and went against previous Final Fantasy titles design. The subsequent additions such as Final Fantasy XII-2 have attempted to add more exploration to the game and it seems that Lightning Returns: Final Fantasy XIII may be expanding this even further through the recent discovery of the uncovered map.
Some fans have accessed the Japanese Facebook application for Lightning Returns and ripped maps containing the four main regions of the game. Whilst not entirely open world it does seem to go a long way in comparison to the original Final Fantasy XIII.
The game is set to be huge in design, although these images make it hard to truly conclude as to what the size will be in the end. What do you hope to see in Lightning Returns: Final Fantasy XIII