This is the topic everyone likes to complain about, however, in my opinion there are only a few places within thanalan and La Noscea where I feel like I'm wandering the same area.

Gridania is much worse and probably the only major culprit of this thing you call copy-paste.

One of the reasons the areas do seem so large and monotonous is because of the transit time between place to place when walking. At walking speed, the monotony is heightened because you are slowly passing every element by. If we were rushing by on chocobos to get to places, I don't think we would get the sense that the world was one repeating mess after another, in fact, I think we would enjoy the large expanses of land on which to roam.