The point of this post is NOT to talk about who has the better art.
The three of them are credits as characters designer (aside from other works but they aren´t part of the disscusion) in the respective Final Fantasy game(s) they were involve. Recently some questions came up to my mind:
1. Did they only made the art for said character(s) ?
2. Were they involve in the character(s) background (past/personallity/ideologies/etc) as well as their development ? How extensive were their role in designing them ?
3. In relation to question n°2, isn´t it what the writer (and maybe the director?) of the game is suppoused to do is it ?
You know, this is an interesting question, especially concerning Nomura, because of how earth-shattering FF7 was to exploding his career and making him a game development force. He's often credited as the 'father' of Cloud. but the thing is, he didn't actually do any of the story stuff for that character. He contributed some minor things story-wise, but FF7's story and characters were provided by the following: Hironobu Sakaguchi (Producer), Yoshinori Kitase (Director/Writer), Kagushige Nojima (Writer).
Also vital were people like Motomu Toriyama, Jun Akiyama, Kazuhiko Aoki, Hiroki Chiba, Kazuhiko Yoshioka, Keisuke Matsuhara and Hideshi Kyonen, who were all Event Planners. This meant they actually programmed story sequences into the game, basically. In fact, every scene in FF7 has a 'signature' saying who did it in the code, so you can find out who did what. (We know from this, for instance, that the pervy Honey Bee Inn joke scenes were almost entirely Toriyama's baby, and a few scenes were actually cut from there (but can still be found in the game code) for being too racy.
Nomura did, however, provide all the designs for those characters. He also wanted to try his hand at story, and Kitase allowed him to, and so there's two characters in FF7 that Nomura did design and create in all aspects: Vincent & Yuffie. It's no coincidence that these pair are separate from the main plot and skippable - it's because they were designed away from the core plot of the game by Nomura as a sort of side project. This also helps to explain why, when Nomura took over the FF7 series, Vincent ends up having his own game and a huge role in Advent Children, and why in Vincent's game Yuffie is the second most prominent character - he was giving his children some attention, basically. On those projects, he took over and on the FF7 compilation stuff he was the driving force on story stuff.
Nomura can be credited for one or two additional things, though - while Blitz/Trance existed in FF6, Limit Breaks were his idea, presumably as he wanted to see his designs pull off cool/big moves. It's in small ways like this that you feel Nomura's hand on FF7 and its story, but the overarching plot was provided by Sakaguchi's rough direction and then cemented by Kitase & Nojima.
For FF8, Nomura took a more hands-on role. The story again wasn't really him (that was Kitase and Yusuke Naora), but Nomura actually provided all of the character backgrounds to fit within that story; he gave them their personalities, basically. So his influence on all of those characters is gigantic. He was similarly more hands-on with FFX, but again, you can't really say the story is his. His work on FF11 was just contributing some rough base concepts, and for 13 he had no hand in the story and simply designed the characters to spec of the designers.
Amano is essentially a gun-for-hire (though an incredible one), and isn't really part of the Final Fantasy team proper. He was always just sent specifications and story details by Sakaguchi and drew to that.
Yoshida, also, I think is a more hands-off artist - unlike Nomura, he doesn't have directorial aspirations or what have you.
Hideo Minaba, who did the art direction on FF9 and designed most of the main cast (and later worked on FF12 & the 13 series) seemed to be somewhere in the middle, deeply involved but not exactly setting the tone himself.
