FFTA2 is not only a worthy successor to the original, but it surpasses it in almost every way.
FFTA2's story overall is similar to that of the original's. Luso (the main character) finds a book in a library and is thrown into the world of Ivalice. Luso joins up with a clan withing moments, and his adventure begins. The book does play some significance, though. Luso and Cid (the former clan leader before Luso shows up) believe that filling the pages of the book will end Luso's 'story' in Ivalice and send him back home. Filling in the pages of the mysterious journal requires completing certain missions.
It should be mentioned that the story does have some interesting plot twists and overall a darker feel than the original. I can not go into great detail however, as I do not want to spoil anything for anyone. Side quests also branch off into their own game within themselves. Some quests end up chaining into several quests which could serve as their very own game.
As far as characters go, there's quite a cast. Luso is rather naive and tends to do things without thinking. Cid is a simple man with a deep, troubled past. Adelle, a gifted thief with a knack for... thieving. Finally Hurdy, a bard who more interested in new instruments than one should be. In addition to the standard cast, there are some familiar faces from other Final Fantasy titles such as Vaan and Penelo from FF12 and FF12 Revenant Wings, and Montblanc from the original FFTA. There are, of course, several others that hold some significance, but most supporting characters will not even make an appearance until the end of the game after you have beaten the main game.
Missions there are a plenty... but what about variety? As far as mission objectives go, most involve simply defeating all enemies or just one foe. Others try to be different, but end up having the player defeating everything just to get rid of the annoying AI and then completing the objective(s). At the end of a battle, the clan members will acquire their experience and the clan will get their reward. Sometimes a clan member will get an MVP award, making them more likely to succeed in dispatch missions with every additional MVP award. Missions also vary in difficult (obviously) but for different reasons. Some of the laws are just ridiculous in some missions. Some laws forbid things you can't control such as the 'Missing' law or 'No Knockback' (critical hits count as knockbacks). The main quests are significantly more difficult (although generally have less restrictive laws), and the last quests are such as step ahead that I usually took a few minutes for most battles until the final quest which took me well over three hours (the final quests is divided into two parts).
So the big question is, "Are there still judges in FFTA2?" The answer is, "Yes," but they are nowhere near as annoying. The new law system is much more lax. At the beginning of every battle, you can select a certain bonus, called privileges in the game, that affects the clan such as increased speed or power. This bonus remains as long as the law is not broken. Obeying the law gives you bonus loot (usually nothing helpful though) that can be used to make items (more on that later).If the law is broken, the clan loses their privilege, bonus items (anything gained during battle from defeated enemies or chests is still kept), and any fallen allies remain dead until the end of combat.
Aside from some unfair laws, the game does have some other issues. Because of the camera view and the terrain, mostly the elevation, players may think that a target is just one or two spaces away but they are actually 4 or 5. Other times where there are no panels present between two pieces of land may have a similar problem because the game automatically brings your cursor to the next piece of land instead of the next block. Some missions can be based entirely on luck as well. Sometimes you will have to kill a certain amount of a specific kind of enemy. The problem is that you can only kill that type of enemy, and there is an enemy cap so the respawn doesn't fill the map with enemies. Sometimes the monster the player needs to kill doesn't respawn, making them either restart their game from the last save or failing the mission and retrying it later.
Character classes are much more balanced for the most part. No class is incredibly superior to the other, and several of the best classes from the original have been nerfed. Mixing classes is no much more important than before. Magick based classes have been affected the most. MP now starts at 0, but characters regain 10 MP instead of 5, making the player think twice before using that Ultima attack or healing an injured clan mate and making support characters much more useful. Some classes, however, like the Parvir which can deal out damage like nothing. The most broken class of all is the Ranger. Using Item Lore as a Passive Ability and using a Mirrored X-Potion results in a high accuracy 400 damage attack. So while some classes have been balanced out, others like the aforementioned are just overpowered.
Moving around on the map has been changed as well, and for the better. The world map now has regions, each region containing smaller areas where quests take place. Moving between regions takes 1 day while moving across an area takes up no time at all. The region with the next main quest will have a blue exclamation mark on the world map to help the player locate the quest (even though the region is displayed in the quest info). Speaking of quests, there are now what is known as clan trials, which after being completed give or improve certain privileges.
Even the item shops have been revamped as well. In FFTA, new items were added by simply completing certain quests. In FFTA2, there is a bazaar. The bazaar uses loot obtained from battle that would otherwise be useless and can transform it into a piece of equipment or items which can then be used to learn new abilities provided the equipment has any. Most equipment made in the bazaar is infinite supply, but some more powerful weapons can only be bought once per loot synthesis. Eventually the player will gain the ability to buy chips using CP, which is earned after battle.
Another way to gain items is through Auction houses. Auctions are held yearly in FFTA2 and always hold some rare items that would be difficult to create through the bazaar. Auctions themselves are mini-games where the player uses chips of a different value (and limited supply) to try to end the round with the most chips on the board but still have enough to continue to win in the other rounds, so there is some strategy to auctions. However, to be able to compete for items, the player must first be the master of the region, which means they must win the auction for all of the areas for that specific auction house.
The problem with all of these additions is that by the time the player might have began to understand one thing, another thing comes up. Players who have not played FFTA will more than likely be completely lost. There is just so much depth to the game, that the game almost suffers from it. Players of the original will not have many, if any, problems figuring everything out the first time.
Graphically, FFTA2 is one of the best looking 2D games ever created. Attack and magick animations are amazing and crisp. Landscapes look as though they were painted with a pastel brush. The sprites are not as great looking, but making a good looking 2D sprite is just about impossible with the character sizes FFTA2 has.
The sound quality is equally fantastic. Musical scores, while small in number, are some of the best on the DS. Sound effects have been greatly improved as well. The only hindrance to the sound is the quality, or lack there of, of the DS speakers.
Final Fantasy Tactics Advanced 2 is one of the longest games ever created. Completing all 400 missions will run the average player around a whopping 150 hours of gameplay. Completing the main quests will only take about 20-30 hours, leaving the length open to the player. While the ride may long, it is certainly enjoyable. With great production values and improving on virtually all the flaws of FFTA, FFTA2 is not only a worthy successor to the original, but it surpasses it in almost every way.