Even if something has concept art, that doesn't mean that thing is going to be featured as a fully explorable city: it might just be to establish a certain place for cutscenes or setpieces, or for paintings. Or it might just be something that has been scrapped. It's not about hype, it's about realistic, safe expectations.
I mean, the fact that they have only empashized Lestallum and Altissia kinda tells me there aren't any other villages or cities, only settlements and such. Hopefully Tenebrae is explorable, at least some of its buildings. But lol, don't even expect Niflheim, as it wouldn't make sense in a story context unless things change from what the initial premise is. It also looks huge (inspired by Manchester? It kinda looks like that in the loading screen), so more reason for the "no".