This difference in approach is actually visible from differences in map geography. To examine a small sample, here are the overworld maps in Baldurís Gate, Morrowind, Oblivion, Fallout and Fallout 2. By contrast, here are overworld maps from Dragon Warrior 3, Lunar, Lunar 2, Phantasy Star 4, Final Fantasy 4 (B), Final Fantasy 6 and Final Fantasy 9. The mountains in the Fallout games are passable; the mountains in the Elder Scrolls games are sometimes passable; mountains in the others are not. Compare the frequency with which one encounters impassable mountain ranges or oceans among the wRPGs versus the jRPGs. Notice anything?
In the jRPG maps above, you can actually see that the liberal use of impassable mountains and water effectively turns large portions of the world into corridors between two or three visitable locations. Exploration is thus rendered highly linear. In recent years, Square-Enix seems to have decided that it isnít worth keeping up the facade, and has shed the overworld entirely.