Anyone would've been great But if there are any Final Fantasy 13 sequel again or spin off. These are my opinion. Some of these includes some spoiler, I think.
''No one ever said the future would be easy. But I think we all saw the glimmer of a dream, somewhere in the sky that night. The tiniest spark of hope that we could change our fate. Who could say? That moment has come and gone.'' Final Fantasy 13-Oerba Dia Vanille
''When prayers turn to promises not even fate can stand in their way.'' Final Fantasy 13-Oerba Yun Fang
If Vanille I think she need team up with Fang in some Action game. Since they're almost always together in Final Fantasy 13 sequel, except in Lightning Returns I think. Well the gameplay should like Final Fantasy 15 maybe great. The story of former L'cie from Gran Pulse. Maybe it should take place when the War of Transgression. And yeah Vanille's weapon should change to some staff. Fang I think she should keep her spear. It's pretty cool. Oh yeah job, for Fang I think she's a dragoon? Vanille is White Mage and Black Mage.
''The world's full of lies. There's is no way of knowing what's right. All we can do is believe in ourselves. It's easy to sit back and let people trick you. I might not make all the right choices. But as long as I'm the one who decided what to do, there's nothing to regret.'' Final Fantasy 13-Hope Esthiem
If Hope, well solo of team up with anyone maybe great. The story, since he's almost think everything through. Well Action if I put it. The story kind of mix up with anyone maybe haha It would've been a good thing if he change his weapon to some sword. I think Hope is a White Mage.
If Snow, I really want to see his solo action. The story might be take place when he off to find Lightning after he left New Bodhum. Punch everything in his way haha Kind of curious what happen to him after he left New Bodhum. Although I already read 13-2 novel Fragment Before. For the weapon his punch is enough haha
"I'm not giving up, but there are something that you just can't change." Final Fantasy 13-Sazh Katzroy (is this the words that Sazh said? I kind of forgot )
If Sazh, I think solo action. The gameplay, since he always carried dual gun so it should take gameplay like Final Fantasy 7 Dirge of Cerberus with Vincent Valentine as the main character in his solo role. But the story kind of mix up with comedy action and yeah just like his personality. And of course that chocobo chick would always folllowed him. And chocobo chick should have some special technique (is this the right word?) which team up with Sazh. The chocobo turn into some magical bazooka weapon haha For the chocobe special technique, it would call so many of chocobos. Couple of chocobo hordes that hits the entire enimies I wonder if they fought cactuar, would be some funny battle.
''But, the past is what makes us who we are, defines us as people. The future that we're aiming for, that's the thing we can change. No matter how bad things have been, wihtout that past I wouldn't be who I am now.'' Final Fantasy 13-2-Noel Kreiss
If Noel well after events of 13-2, it about his journey after the of 13-2. 500 years what happened in that 500 years. Maybe he defeat some chaos monster too. Not much of the idea how the gameplay and the story should like. I think he's Hope in Final Fantasy 13-2. Not in personality, but some wise words. Since he said so many wise words in Final Fantasy 13-2 like Hope in Final Fantasy 13. I kind of like his dual sword. So it should stick with him.
"Kupo! Kupo!" Moggle-From every Final Fantasy game (although I'm not sure when did Moggle make its first appereance in Final Fantasy. I think between Final Fantasy 2-6, but don't know which one. If I'm correct it was from Final Fantasy 2 or 3.)
I wonder, is there any Final Fantasy game that focus on this cute little thing? Well they should make one Kupo! The gameplay should take something interactive, cute all kind of thing that related to Mog. Either its solo role or team up. No one could resist to play as Moggle, I think haha For its weapon I haven't consider it.
''When the path ahead is too dark to see, sometimes it's important to just keep going.'' Final Fantasy 13-2-Serah Farron
Well if Serah she should be play as a team. With Lightning and Snow. The story might take event after Lightning Returns. Gameplay maybe action or original ATB system. Either both. Serah bow-sword is pretty much cool.
Above are for the protagonist characters in Final Fantasy 13 and 13-2 (is protagonist the right word?)
Now down below are for the antagonist characters in Final Fantasy 13 and 13-2 (is antagonist the right word?)
"Power of chaos bend to my will!" Final Fantasy 13-2-Caius Ballad
The story and the character Caius and Yeul. Might be take events when they're traveling in Final Fantasy 13-2. I mean, what did they do when they're traveling? The gameplay either action or ATB system. I prefer Caius keep his sword it really creepy some sword and Yeul kind of wondering what weapon she should equipped maybe that flower that she always carry with her. Caius I don't know what job he is. For Yeul she should be White Mage and Black Mage.
"L'cie, bound to an inecapeable focus. Slave of destiny." Final Fantasy 13-Cid Raines
I'm kind of confused what role Cid should play. Of course he has his Cavalry with Rydea as his top lieutenant. Maybe Strategy. He command his airship to fight PCICOM, maybe. Or some action game. For weapon well he has his airship and army for strategy. For action mystical power I guess.
Since Lightning has been main character for 2 games. It's good to let the other characters take place for main character. And these are the only characters that I could think of.
I think many of them are wrong, feel free to correct them.
Sorry if my english not so good
But this is my opinion