It's hard to completely hate this game due to the sheer amount of effort put into it.
The storytelling felt very lazy, right off the bat they throw all these references about things you couldn't have known about if you play this game for the first time. So how are you supposed to figure out? They give you this giant encyclopedia to look things up, and not just for 1 chapter, for every chapter in the game. Besides that the characters weren't really sure what to do until about 10 chapters in and the ending doesn't really clarify much, it was just a very unpleasant experience.
The graphics are great, everything is very detailed and artistic, the battle and cutscene animations look very fluent and crisp. There's also a great variety of things to see, such as a crystal lake, a tropical forest, ruins. However at the same time it feels very shallow, you can't really explore anything. I know it's been said before but it feels like a corridor. You can't go anywhere except the roads you are supposed to go, there will be a few branches but they only lead to dead ends with occasionally an item.
I know I've whined a lot about the story and graphics, but you can forgive a lot in a game when it has good gameplay right? Well sadly it feels like there isn't a lot of gameplay.. As I said earlier, there isn't any exploring to do since you can only follow one straight road, and there aren't any towns, real npcs (you'll see a few that will say something if you stand in front of them but there's no real interaction) or side quests that don't involve killing monsters (which you probably do enough already in the main game) and the shops are just menus at save points. So what about the the combat system? There are 5 classes and you can assign any character to any class. The classes are pretty straightforward just awkwardly named. You have commando (warrior), ravager (offensive mage), medic (defensive/healer mage), synergist (buffer) and saboteur (debuffer). Although usually 2 classes are pointless since every character only specializes in 3 and are really crappy in the remaining 2. As you level up you get points to put in this crystarium, which contains nodes of str up, magic up etc. Although this was pretty pointless as well because you have to follow a specific path so you don't really have a choice in where to put the points in. Again there are a few short branches but you're not really free to assign your points however you want. For example there is no reason to put points in strength for Vanille or Hope (the mages in the game) yet you have to because otherwise you can't access the next node.
In the menu you can set up any combination of classes that you can switch between anytime in battle. Which is pretty clever.. in theory.
However sadly the battles are nothing to write home about. It's a turn based system where you have these bars that gradually charge over time, which increase over the story, simple attacks cost 1 bar and multiple enemy/advanced magic attacks cost 2 or more you control 1 character and the other 2 are AI controlled. This doesn't really matter though, because the first option AND most useful option is "Auto-Attack" the AI will automatically pick the best combination of moves anyway, even elemental weaknesses and such. So there's no point in manually selecting the moves since the AI would probably pick the same, and sometimes better anyway. The only thing the game involves you with is sometimes scanning the enemy and occasionally switch classes on boss fights, besides that you'll only be mashing X all. the. time (no exaggeration). You can also use summons but it boils down to the same thing except you can use a special attack which is best to use right before the summon dismisses because after you use it the summon will automatically leave.
The money/equipment system is very unbalanced. The monsters don't drop money, but only items instead. Although most are only useful for upgrading equipment, so there's a big chance you'll have no cash for about 7 chapters until some random enemy drops valuable stuff you can sell. You can shop at every save point and you can buy equipment, upgrade material and potions, which is pretty useless since you restore HP after every battle. Now as I mentioned before you can upgrade your equipment but it's pretty frustrating, why? For example, if you upgrade a weapon early in the game you'll be royally screwed over because a few chapters later you'll find a much better weapon, but you can't upgrade it because you already spent it on your earlier weapon, and disassembling the weapon won't even give you 1/10th of what you spent on it.
So finally on to the sound. Some tracks were really nicely composed, actually most are, but it feels like it only has 1 string on it's bow. Most of the tracks sound peaceful, harmonic etc. Usually I feel pumped when hearing battle themes, especially Final Fantasy ones, but this one just felt modest.
The voice acting is nice I guess, they fit the characters nicely and portrait the emotions well.
In conclusion: it's visually gorgeous, but held back by bad exposition, linearity and a battle system that barely involves the player.