He might've felt that a European-based setting was more fitting for the theme of Giants attacking humanity, like in Norse mythology, which heavily influenced some aspects of the story. He definitely considered a Japanese-based setting very early on though, as seen in Attack on Titan 0.
The European setting of Attack on Titan confuses me on which country this series is actually from and Attack on Titan anime sounds better in English compared to Japanese because of its European setting unlike Naruto Shippuden and Naruto which sound better in Japanese compared to English because of their Japanese settings.
Because the only European language that the series sounds the best in is English and even in a Japanese setting the story could be also very nice as not all the Asians possess Levi's superpowers. They could make a setting where people are fighting Titans in a remote Japanese village surrounded by three 50 metre walls and Titans are transformed humans that are also injected with the Titan serum.
I know that. I think the series will be as good as it is now with a Japanese setting but I am ok with the European setting anyway. I think that the manga should be released weekly so I don't have to wait till next month to get to read the next chapter.
If it was just a Japanese location, it wouldn't seem large enough. The chosen setting has much territory, even in a confined space.
I know. That is why I said I am ok with the European setting. The only thing I dislike about Attack on Titan is that it is released monthly instead of weekly because of that I have to wait till next month to get to read the next chapter instead of next week.