I agree with your whole post, but especially on that. This is why i think that FF9 was just an easy cash-grab for Square. People can say what they want about FF8 but at least Square tried something else with that game.
I liked FFVII and FFVIII, but I absolutely adored IX (easily my favorite PS1 era FF). I really liked how it returned to its medieval inspired roots (castles, airships, knights), and away from the sci-fi futuristic worlds of FFVII/VIII. I just found that IX had so much "heart" to it. From the characters, to the setting, to the whimsy, and to the story (even though the shit hit the fan in the end), I just found a lot to love from the game.
Plus, I really think the love story between Zidane and Garnet was really well done. It didn't feel "forced" the way Squall-Rinoa was (at least to me). And that ending where Zidane comes back and Garnet just runs to him, while plowing through a sea of people is right up there for me in terms of greatest video game endings ever (I really liked FFX's ending too, so I really hated the fact that they ruined it by creating FFX-2).
To be fair, I haven't played the entire series. But I have played most of them. I've played III, IV (didn't finish it on DS), VI (playing this right now and loving it), VII, VIII, IX, X, XII, and XIII (skipped the sequels). I haven't liked an FF since X (didn't like XII that much though I'm really interested with the remaster as I wasn't able to finish the game) so I'm just hoping that XV is a good game. At this point, more than anything, I just want it to be good.