Obviously at this point it seems there could be a lot more filling the zones we travel through in FFXIV, and what there is in them could use some more content. However is it necessarily a bad thing that there is so much empty space? When I think about future content that could be added in the various zones I think not. Also even without more added once there are mounts and airships and whatnot placed in the game maybe it will all start to seem much smaller, who knows? I also think it's a good thing because you can wander out farther from the shmobs of people next to the camps and find good grinding spots if you look for them.
Just some thoughts, maybe SE already has plans for some implementations in zones.