Rydia showing up is a great scene and one I definitely remember loving as a kid. Now though... I realize it for what it was. The reintroduction of a character in a dramatic fashion. If Yang showed up and kicked the Shadow Dragon to death it would have probably have been similar in how awesome the scene was. Rydia had such a minimal part leading up to that moment that it really does stride into the DEM territory. It is explained afteward, but when it happens it really is out of left field to the point of almost being silly. Brahne getting killed and semi-reconcilling with her adopted daughter is easily as moving and as surprising as it should be... who the fuck thought Kuja was the -real- badguy at that point unless we used Japan Logic to solve it. Golbez being Cecil's brother is really one of those JAPAN! style tweests that really didn't need to be there but does add to the story. Zidane being a construct designed to obliterate life on Terra that gets accidentally reprogrammed isn't a twist; it is a decisive story angle that makes complete sense in the context of the story.
Look, I don't want to keep harping on this, but there is some stuff being glossed over here and it's clear that there is some storyline depth being taken for granted. Yang showing up and karate kicking Golbez
would nothave been the same. This wasn't just character believed to be dead showing up out of nowhere, there is more nuance present than that.
You don't see Rydia first, and it's not some random summon or even Titan that saves you. It's "MIST DRAGON! Wait, what?" Yes, the summon that you slew that was a direct cause of tragedy in this girl's life is now showing up to save you and it's not only wielded by the girl(now a women,"Huh, How?!"). She is fully grown, strong and self-assure, completely different from the little girl you had to convince to be able to cast a simple fire spell not too long ago. There is more present here than just CHARACTER MIRACULOUSLY returns, and as much as you like to dismiss emotional personal "fill-in the blanks" there were conscious design decisions that create storyline
beyondthe limitation of the medium. There is a reason I didn't select Yang stops the Doom Cannon or Cid seals the underworld as my example.
The sequence from creepy doll spying on you to Rydia's return to Golbez showing how truly powerful he is by snatching victory from defeat is easily one of the best in the game and is an example of storytelling in spite of a limited medium, not a limited medium allowing for great storytelling by the viewer's imagination.
As far as 9 goes, he's my major gripe with it. Brahne. Besides being inexplicably hideous to look at, her motivation is never really explained. Kuja shows up and tells her she needs to conquer everything and that's that, she goes from normal to terribly, terribly evil? There is no mind control revealed, and once Kuja betrays her she inexplicably decides she's going to be nice again. It's all terribly contrived and smacks of the same
twist!bullshit that gave us Necron at the end.