Just some random thoughts and impressions:
-I know the Ch.0 stuff is likely heavily edited here, but even then the game sure drops you right in, doesn't it? You're set loose in a field and given a few minors shops and things withing 15 minutes of New Game.
-I love the customization of the magic system, but only having three elements, plus the way it's tied to what's essentially a "grenade" mechanic feels like a weird bummer. Taking up a slot on your action palette is also a huge disappointment. So if you want to have, say, one spell of each element available, you can only have one "weapon" on you. I really hope there's a Kingdom Hearts-style Shortcut Palette that gets unlocked, or something.
-Only one special ability per party member at a time? What? That can't be right. How ridiculously, disappointingly constrictive - as is the apparent total lack of control over party member's behavior or when you trigger combination attacks.
-Hopefully the "Astralsphere" isn't as small and straightforward as it appeared in the video. Maybe there's additional "pages" or something? I'm getting pessimistic vibes of XIII's Crystarium, which was just a complete straight line with occasional "branches" that just dead-ended after a node or two. Please give some real flavor and role-definition to growing these characters.
-Clothing customization is great. Hope there's a good variety of pieces. Fantastic that they seem to be striving to keep things in-engine as much as possible, too, so you'll always be dressed the way you want. Noctis in a puffy vest and baseball cap during somber moments is pretty hilarious.