Even though Final Fantasy VII was Square's big commercial breakthrough, I think that it's actually Final Fantasy VIII that has defined the latter-day Final Fantasy series. I thought that Final Fantasy IX was very similar to its predecessor. Final Fantasy X is very similar yet again.
But in many parts, the game creates a feeling of "Final Fantasy VIII done right." I enjoyed Final Fantasy X more than the previous two installments, and I think it has the best gameplay out of all of them. For most of the game, there are very sharp distinctions between the characters, sharper than they've ever been since Final Fantasy VI back in 1994. And the game forces you to make full use of these distinctions -- for a long time, only Wakka can kill flying enemies, only Auron can kill armoured enemies, only Tidus can kill "nimble" enemies, and only Lulu can kill magical enemies. In fact, you have to heavily rely on your attack mage Lulu until quite late in the game.
Furthermore, this is the first Final Fantasy game in a long time where status-changing attacks and spells actually matter. Status effects like poison, darkness and petrification are much stronger and more deadly in this game than ever before. Defense-boosting spells like Protect, Shell and Reflect turn out to be the key to survival in many boss fights. And these things are just as effective when reversed -- the enemies are much tougher when they Protect themselves, but using a turn to Poison them can now be a very effective tactic.
Further still, some bosses actually require you to think strategically. One boss toward the end of the game has an instant-death attack against all characters that never misses, as well as another attack that inflicts Zombie status on everyone. This status makes it so that curative items and spells damage your characters instead of healing them, but it also lets you evade the instant-death attack, so you actually shouldn't cure all your characters. In this way, combat is tougher and more strategic in this game than it has been in years. It's likely that you'll lose many times in later battles.
I should add that the battles are more fast-paced here than in the previous two Final Fantasy games. The camera is much less hyperactive than before. Battles set up very quickly without all of the flying camera angles. And the battles usually have around three enemies at a time, as opposed to one or two like in the previous installments.
The game is also a little less reliant on Final Fantasy iconography. For example, there are fewer summons than before. Out of the "usual" Final Fantasy summons, only Ifrit, Shiva and Bahamut appear. They are still powerful, but you have to use them strategically. The toughest summon is Anima, an impressively horrific original creation. Also different from earlier games is the lack of a world map (different locations are connected to each other by roads that you have to travel), and the greatly reduced role of Cid and the airship.
The characters are reminiscent of Final Fantasy VIII, but better. Again the story centers around star-crossed love between Tidus and Yuna. But I personally found Tidus, a cheerful surfer-boy type, much more appealing than the monosyllabic Squall. Yuna is kind of nice and earnest, and at least has a more well-defined personality than Rinoa. Among the supporting characters, the devout sportsman Wakka is also very appealing. All the dialogue between the characters is spoken by voice actors, who do a surprisingly good job of defining the characters' personalities (the guy voicing Wakka is particularly good).
There's also a lot of interaction between characters. Between all major dungeons and boss battles, there are short scenes of the party resting where you can talk to the other characters. This is also quite nice, since it makes the characters seem a little more alive than your bland team-mates in Final Fantasies VIII and IX.
But unfortunately, the game shares many of the problems common to latter-day RPGs. First, the plot is revealed in an annoyingly vague manner. Characters like Auron constantly pester you to keep moving because there's "no time to waste." They drop little hints about the plot and talk in vague riddles. I know why the game is written like that -- it's supposed to keep the player guessing until the Big Revelation finally arrives. But the problem is that all of the Big Revelations are painfully obvious, and you can see them all coming hours in advance. Your other characters, unfortunately, keep on talking about these things like they're important. Yuna's dialogue is mostly about her determination to save the world. Admirable, maybe, but really monotonous. It's an RPG, I already know she's going to save the world. Let her talk about something else.
The main antagonist of the game is a big demonic force-of-nature type of thing called Sin. This is actually a really cool idea -- it's more original to make the villain some kind of giant personification of nature or fate rather than yet another power-crazed maniac. But unfortunately, the designers weren't brave enough to just go with that idea, so they added a power-crazed maniac as a second villain. This is the worst part of the game -- all of the dramatic scenes with this second villain are handled incompetently. First, the justification presented for why he's so dangerous is paper-thin. There's no reason why he should even be in the story. There's a long subplot involving Yuna's interaction with this villain that just becomes ridiculous after a certain point -- first she agrees to go with him! then she doesn't agree! then she goes with him! then he wants to kill her! then he doesn't want to kill her! then she wants to kill him! then she doesn't want to kill him! It becomes obvious that the only purpose this subplot serves is to increase the running time of the game and to provide excuses for dramatic FMV and boss fights.
So a lot of the scenes that should be dramatic and powerful are botched, because the designers evidently couldn't separate the good ideas from the bad ones and focus on the good ones. To add to that, the world of Final Fantasy X is just not very detailed. The designers packed the DVD with so much FMV and voice acting that it often feels like there wasn't room left to sketch out the setting of the game. To wit, there are only four towns in the entire game. One of them is supposed to be the second-biggest city in the world, but you can only actually go to the sports stadium and a little plaza with a bar. There's another city which is supposed to be the biggest city in the world, but that one you can't go to at all -- you visit one room of the palace for a story scene, but that's all. You can't go into the city itself -- the guards will never let you through the gate.
Similarly, the dungeon design is very basic. It's nice that there's no world map, but this just makes the game extremely linear. There is no exploring at all in Final Fantasy X, not even to find where to go next. You go from A to B in a straight line. And I really mean a straight line -- almost all of the dungeons consist of roads. There are no mazes at all. At no point in time do you ever have to think about where to go. The final dungeon is really quite boring, just two long rooms and an item-collecting event at the end.
To make up for this lack of interesting content, the designers threw in massive amounts of sidequests. This has been part of the Final Fantasy series for a while, but here it is taken to ridiculous extremes. The main game takes 30 hours to beat. If you want to do all the sidequests, collect all the ultimate weapons and so on, it takes 70. The sidequests literally take longer to complete than the main game.
And the sidequests are unbelievably boring, frustrating and mind-numbingly repetitive. It's not enough to just go and find the ultimate weapons. No, you also have to gather items to power them up. One item requires you to play a butterfly-catching game, another requires you to win a chocobo race with horrible play control, another makes you dodge 200 lightning bolts in a row without letting you save in between. All of these tasks are repetitive and annoying. Another item requires you to play blitzball, which is fun for a couple of hours, but not when you need to play at least 40 games at 10 minutes each.
The biggest sidequest involves capturing monsters from around the world, but here again, you need to capture 10 of each kind to complete it, and some of them are pretty rare, so you'll just be running around the dungeons for hours, fighting the same enemies over and over, just to find the rare ones. If you finish at least part of this quest, you can access many secret bosses. They'll be ridiculously tough, many with millions of HP. But, unlike the bosses in the main storyline, fighting them is not strategic at all -- you just need to break the game by gaining huge numbers of AP and teaching all abilities to all characters, which makes them super-powerful and totally erases the interesting distinctions between them.
I really dislike this trend in games -- instead of trying to hide the deficiencies of the story by padding the game with countless repetitive and pointless item-gathering, followed by equally repetitive and pointless boss fights, it's much better to just have one secret dungeon that actually requires some exploration, like in Star Ocean 2, and preferably has some bearing on the plot, like the crashed Gelnika in Final Fantasy VII. Even better, why not just work the difficult parts into the main game, where they could be integrated into the story?
Final Fantasy X doesn't really feel original and revolutionary the way Final Fantasy VII did when it came out. It feels like a new take on Final Fantasy VIII. Often, it feels like a superior take, but it's plagued by overwrought scenario planning and lazy set design.