I hope this isn't the reason Final Fantasy XII was delayed...
A highly customizable character selection screen is about the only interesting part of the game. After this process, you just hack, and hack, and hack your way through the same few dungeons dozens of times. The game forces you to level to get the better equipment and that means completing some of the most mundane of quests to gain experience and any reward which accompanies the quest.
A decent variety of attacks makes combat not as tedious as it could be with just a sword and the physics of the game (the ricocheting) has combat outcome pretty comical when the screen gets busy with enemies. I don't use the magic system (good luck if your a magic user) so I don't have any details on that aspect of the game but with only one magical attack and one magical powerup spell, I'm going out on a limb and saying it can't be to deep.
The gem fusing system has a few redeeming qualities to share with the game. All your hard work can result in some truly powerful gem combinations for your character.
I have yet to try the multiplayer but then again, if I don't like the game, why would I make any of my friends buy it...
I'm patiently waiting my turn to play FFXII from my bud and hopefully I will be long through with Children of Mana.