The Layman's Physics Discussion

[Enkidoh]

As long as we're asking the tough questions: Can you prove this premise you're working off?

If you stand in Kugane and a friend stands in Ul'dah, and you share the positions of your shadows by linkshell at exactly the same time, they'll be the same, despite having a full continent between you in either direction. No matter where you are in the world, the sun is in the same place relative to your position, the clocks are the same, all of it. That shouldn't be the case on a spinning ball-shaped Hydaelyn.

And have you ever seen anything disappear over the horizon? I haven't. There's usually a mountain or a zone border long before you could, to disguise the mind-blowing truth: FLAT HYDAELYN.

the ascian moon cutscene was shot on a garlean soundstage

So the first few moments of ARR's opening movie, plus the 'stinger' scene on the Moon and the model of Hydaelyn on the Astrolabe are a fib, a lie and a bald faced whopper then?

Seriously though, the aforementioned instances clearly show Hydaelyn as a round planet, regardless of what technical limitations the in-game skybox may have in depicting accurate celestial mechanics, which is only to be expected, as the game is not meant to be a virtual simulation of Earth.

Also, there is a handy hint in the game's title, as in, it's fantasy. Science-fantasy to be specific, but fantasy none-the-less, so trying to correlate hard physics in such a setting is never going to end well (lets not forget this is a world where a giant aetheric dragon was encased in an artificial satellite for millennia and the planet itself is not only a living, self-aware entity that takes the form of a giant sentient crystal, it grants psychic abilities to random mortals). So yeah, this is fantasy. Don't think about the 'science' behind it too much.