I think it would have been better if they allowed you to customize the conditions for specific actions per character. Sure, you could argue that there'd be too many characters (up to 25?).
It's not really like gambits and whoever said that hopefully explained why it's not like them. If you go in thinking this will be anything like FFXII, you will be wrong. You've got to start thinking of unions as characters and you can customize your "character" by the swapping around the members inside of it.
I'm currently using three unions with five characters in each. One union is typically more melee focused, one mixed, and one magic based. This totally depends on the unions you've picked to join you. Some units cast spells, some do weapon based attacks, some are potion focused for buffs/debuffs, some are a mix. It's up to you to decide who to recruit and then up to you to decide how to organize your unions.
Right now, I can use a max of 15 characters total, only 6 of which can be the more powerful leader characters. I can create up to 5 unions. Since HP and turns are shared throughout a union, I currently only am using three unions with the max of 5 characters in each. If I wanted, I could shuffle some around and have four or five unions with fewer characters, but that's not what I want.
I hope that makes sense. If not, ask and I can clarify.
The pacing of the battles.
I love the boss battles, as hard as they are, because they feel like boss battles. You have close calls and have to plan carefully for them and they take a long time. When I finish one, I feel like I've accomplished something.
However, due to loading times (which hopefully NXE might help with), normal battles take a long time, too. It's not horrible and you can avoid them, but you really do need to fight to gain stats and items.
The pacing of the dungeons. ... If the game is designed in such a way that good tactics can compensate for lower levels, good. If it requires you to grind, tsk tsk.
Oh, there are no levels. You gain stats after each battle you survive. Your spells and skills improve as you use them, a la FFII. Want to be more melee focused, keep using melee arts. You can even level up your skills and spells during combat, so that's nice.
The battle system is deep, that's for sure. It's even harder to explain than it is to just get your hands on and figure out, just because there is so much to it.