Hm. I haven't finished 13 yet, but I thought they were rather successful with the characters at least. Most of them inspired deep, raging emotion in me, the likes of which few games can. The only thing that spoils this is that I am still not sure if this was intended on their part. I mean, signs point towards players hating their fighters on purpose: from making you play as them when you really (seriously, really) don't want to, to building them with such weak characteristics that they feel almost like minor antagonists.
Somewhere in there you're relating to your enemies in a very real way. I understand completely why they keep wanting to destroy the playable characters, and most of the time agree with their motivations, completely. It was a revolutionary experience for me, since I had to keep the player characters alive, but wanted to let my supposed enemies win. Is this some small trace of what a suicide bomber feels like? We must destroy everything to win?
Well, ruminations aside, I cannot agree with a continuation of this experiment. You know what, you win Square Enix. I gave up before getting to Gran Pulse, and feel very guilty for not continuing far enough to get there. Your play-as-the-enemies-of-the-people-who-are-actually-saving-the-people-even-if-we're-designing-them-so-you're-inclined-to-aggressively-want-to-kill-them-off-in-the-best-interests-of-their-world-so-no-one-else-has-to-deal-with-them tricky head f*ck did actually work in my case. You don't need to make a sequel. You already won.
Besides, Lightning is just gloatingly happy that she gets to live since she's a title character. She sneers at me from the box. What else could you want? 3-d implementation so she can appear to strangle me, the player, in some ridiculous reversal?