Well part of the issue here is that FFXII is a plot driven game whereas XIII is a character driven piece so it makes more sense that XIII would focus on the characters more and not so much the antagonist (unless they had a personal history with one of the characters which XIII didn't do) whereas XII focused more the story and the story driving villains (cause heroes are traditionally reactionary, while villains are proactive) would get more focus in XII. So a big part of the rift in how both games have their characters written is due to the games being different types of story focuses. Its kind of like poor FFV when people compare it to FFIV and VI, IV and VI are character driven, whereas FFV is more story driven, hence less of a need to go into any deep character development cause how Bartz feels about his past isn't going to help the party beat ExDeath, Whereas Cecil and Terra coming to grips with who they are and their pasts is a major focus and explains what drives them to continue on the good fight for/against *insert generic FF plot*.

When taken into the context of how they were written I feel both games have some issues but I genuinely prefer XII's cast over the oversaturated melodramatic wankfest of the XIII cast.

Ashe coming to grips with choosing to be a wise ruler or a mourning widow is far more complex, better paced and told than Lighting realizing she's a bitch with anger management issues.

Basch choosing to keep his vow of protection of Ashe and Dalmasca despite both hating him and choosing to be an honorable stoic knight is a much more original and well told story, than Snow realizing that he's a gung-ho idiot that causes more problems than solves.

Sahz is certainly a high point in XIII but considering how much he's downplayed beyond the two chapters focusing on him and how he's relegated to comic relief background character halfway through the game so angry bitch and heroic moron can take center stage shows that XIII can't even utilize its best asset well. Baltheir also doesn't get enough air time but at least XII recognizes that he's a charming and amusing character who plays the serious/comic relief card better than Sahz does.

Vaan is bland but he's a bit of a non-traditional heroics youth in that his he doesn't completely overtake the plot as the lead and his growth is more gradual and organic(something The Last Story could have used with Zael), as opposed to Vanille who is a stereotypical genki girl who serves mostly as a giant plot device who spends 3/4ths of the game acting like she's on shrooms and the other 1/4th being in despair about the problems she causes and how utterly useless she is.

Hope... is a poor Ken Amada substitute who acts way too young for his age, and lacks any kind of middle ground, largely jumping from the extreme emotions of despair, hatred, and Friendship is Magic.

Fang has no character development, besides being overprotective of Vanille what growth does he get? Even Fran gets a touching moment about her past and learning she abandoned her family and people to see the world and live in freedom, even Penelo is justified as being the key to a peaceful future with Archades due to her friendship with Prince Larsa, whereas what purpose does Fang serve in the plot? She can actually be totally written out and nothing would have to be really changed except the logo and not having to suffer one of the most painful scenes in the game that serves more as a giant plothole/"wtf were the writers thinking?" moments in a game filled with plotholes and WTF moments.

So yeah... XII is better.