I've been playing for a few days now and I have mixed feeling about this game.  The storyline looks pretty decent for the part that I've seen, but getting to the next bit of story takes too long.  I like the graphics overall, but the graphics aren't as good as the performance hit the game takes when I max them out.  The option to double the speed of the battles is great, since battling is what you spend 90% of your time doing.  
I hate that side quests are mandatory to get your party strong enough to fight the enemies you have to beat to progress the story.  If they're going to make them mandatory they should have worked them directly into the main portion of the game so that you encounter them in the course of the storyline rather than giving you the illusion that they are "optional".  I say this because the battles go from ridiculously easy while you're exploring, to so hard that the enemies are taking out your entire party in a couple of turns for the boss fights.  I'm used to RPGs that give you enough XP during the course of the story to at least finish the story without doing anything else if you don't want to I guess.
Maybe I'm just dumb, but I can't really figure out how the game decides what specific combat/mystic arts to use when I give commands to a union.  It doesn't always seem to make sense, and I can't help but think that I would be able to do a much better job given control of the individual characters myself.  For instance, why oh why would there not be a heal option of any sort when a party is weak, has enough AP, and includes several characters with healing arts.  I can't say how many times I've lost unions because this has happened, but it's been a lot and it's EXTREMELY frustrating.  Also, even when a party is high on AP I'll notice that the mystic/combat arts commands will often have the party leader or some single other member performing a special move with the rest of the party performing regular attacks.  The only exception is when the "Turn it Around" or "Give it all You've Got", or some other special command is randomly available.  When you give me a menu option for "Attack with Mystic Arts",  is it unreasonable for me to expect all the characters with mystic arts to use them?  they should include other options for mixed mystic/regular, combat/regular, combat/mystic, and all regular attacks.   The lack of control over the character's abilities also makes it difficult to fashion unions for maximum effectiveness.  There seems to be no way to make a union attack with special attack moves for that combat-heavy characters while healing or using mystic arts for members of the same union.  If I'm lucky enough to draw a "Turn it around" command they seem to do that, but that's not always available when I need it.  Why do they offer formations that are obviously designed for mage/fighter combinations when I'm rarely able to take full advantage of such a group?  Also, there seem to be times when the game will just do whatever it wants to regardless of which command I choose.  I've noticed characters performing mystic attacks or even healing on rare occasions when I choose the commands that are supposed to make them perform simple attacks with their current weapon.  
All this results in the feeling that I'm not really in control of things, but rather just pressing buttons to make the game get through battles in whatever way it wants to.  The only real way I can influence things significantly is by choosing the groups my unions attack in such ways as to cause flank and rear attacks and tie up enemy unions to minimize their ability to flank and rear attack me.  It may be that the game designers wanted that to be the main focus anyway, but that seems less than satisfying to me.  I guess I'm a micromanager at heart.