The reason is never really given, or at least it's as deep and conciliatory as Yuna's transformation in that first cut-scene. A crowd watches on as the pair embrace, whooping and cheering. Rikku and Paine smile and coo to each other. Kelly Rowland sheds a tear at the beauty of it all.
Meanwhile I stare at my screen, sat in sheer awe of Square Enix's ability to troll me across two whole games and two whole years. That game-defining moment in X, that moment that stood tall, that refused to fold quietly into the foaming mass of blandly perfect conclusions, is so neatly and so very nonchalantly steamrolled into a perfect ending. It was as if the game was saying, "Aw, that sad thing that happened? Don't be sad about it. Here, all better now. Life is always this good, really it is."
And I can never forgive it for that. Up until that point I was prepared to just accept X-2 as the black sheep of the Final Fantasy family, a Super Mario Bros 2 anomaly. But rewriting the ending to what is quite possibly my favourite games of all time? That's unacceptable.
What's so frustrating, ultimately, is that if I were able to step out of myself and my attachment to those characters and their epic journeys in Final Fantasy X, I could probably admit that X-2 does bring some redeeming things to the table, at least outside of plot. Primary of those is the job system based in those lamentable dress spheres - a job system which is full of depth and makes the return of active time battles one of the most electric and strategically interesting in the series history.
It wasn't as balanced as it could have been; the Dark Knight sphere was rather too useful. Nonetheless, working out useful combinations of jobs to employ - and in particular, knowing how and when to switch them around mid-battle, something that was new was to the series - felt fresh. It made for an interesting diversion from the trawling of lists of abilities, an activity that made previous games in the series, including X, feel saturated in options towards their respective ends.
It's that change-on-the-fly job system that is essentially the basis and instigator for how combat works in both XIII and the upcoming XIII-2. Curiously, reflecting on the lasting impression X-2 has left on me, I realize that I'm actually excited about XIII-2 despite my overwhelming disappointment with its predecessor.
My two major problems with XIII were ones most critics share: the opening half was too constricting combat-wise, while the story in the second half didn't keep up with the open-world evolution. What this all means, more importantly, is that there is no all-encompassing, game-defining moment to ruin in XIII-2.
Actually, whereas X-2 had so very much to tarnish (and tarnish it very much did), there's almost nothing to ruin in XIII-2 beyond that combat system which finally came alive in the second half of XIII, and thankfully XIII-2 isn't planning to mess around too much with that. X-2 built upon the mechanics of X while showing complete disaffection and disregard for the story that came before.
That formula is exactly what will make XIII-2 work.