It's a little of both, see unlike you, I never found Spira interesting, and I do partially blame it on the map design making the world feel like the yellow brick road of Oz, so while it is certainly uninspired in its over-simplicity and lack of imagination, I also feel the map design leads to the game not inspiring a sense of being in a "living world" and drawing the player in. So I'll agree with you that it was uninspired design but I also stand that it was uninspiring as well.