At first, I didn't want this and The Last Guardian to be on the PS4, but it might just be for the best. If they haven't been able to run them on the PS3 in the fashion they want, they should just do it on next gen consoles.
Yes, this is the kind of thing I'm hoping for, except extended seamlessly for the entire world. Every FF since X has made use of realistic 3D environments, but they were always segregated into sections, and just connected at very specific points. My dream is to have a world map that looks like the gifs you posted, be able to get into an airship, fly around to another location on the map, land, and continue walking around without seeing a loading screen.
XII was originally meant to be like that. Well, I don't think you were supposed to be able to fly, but you should've been able to go through the world without too many loading screens (mainly between cities and fields). PS2's hardware simply couldn't handle it (with the kind of detail they wanted to achieve with the game), but you can still see the remnants of this at certain places, with how interconnected places are and how you can see areas you can visit in the distance.
