If we were talking about a game like GTA that, while it does have a good story, is much more focused on the gameplay and exploring the world, then yeah a GTA game set in Europe or any other country would be a great Idea, but The Last Of Us has made it clear that, while the world of The Last Of Us is well designed and has some interesting lore, it's main focus is on story and characters, mainly Joel and Ellie. The Last of Us is the story of Joel and Ellie, and the world, while it is a pretty world, is really to show their story. if their story is finished, then their is really no reason to return to that world, and Naughty Dog should make a completely new game, with a completely new world that has nothing to do with The Last Of Us, even it's world. and while it's not boring or cliche, and The Last Of Us does look pretty, but it's world is not that unique. sure it delves into the human condition, and shows how we can become like animals under the right conditions (say a zombie apocalypse), but so does The Walking Dead, and The Walking Dead does almost as good a job at doing so. In it's 5 seasons The Walking Dead has shown us how low people will go to survive, in a similar way that The Last Of Us does, and TWD does give us a pretty good look at the world it's created, but the hole series fallows Rick and his group, another franchise that does this is Mad Max, Mad Max (which by the way takes place in Australia) shows us many different cultures, and a deep and fascinating lore, but it's all shown though the eyes of Mad Max. What makes The Last Of Us, better than The Walking Dead, or Mad Max, isn't it's well realized world or lore (because let's face it Mad Max has The Last Of Us beat by a long shot in that category) rather what sets The Last Of Us apart from all other post apocalyptic anything, is it's story, the reason so many people, including me, love The Last Of Us is because of how much we relate to the main characters, and how likable Ellie is. From a gameplay perspective Europe could be a good location, but from a story telling perspective, totally new characters in a new location, might not be the best way to make a sequel, and since The Last Of Us is a story based game I think they should use the story based approach for the sequel. if you did want to continue the story of The Last Of Us, the main character should be an older Ellie (around 18) Joel would either be dead or, better yet, offer a similar role that Ellie did in the first game, as a helpful AI, Much like Ellie in the first game, Joel could fallow you (now controlling Ellie) and do things like, point out enemies, find ammo for you, and pull enemies off of you when they grab you, just like Ellie did in the first game, this would offer a new perspective (Joel would behave like the player would have in the first one, so playing as Ellie would show us what it was like for her when she witnessed us doing what we did in the first game) without doing something as stupid as making Joel the bad guy.