It's been attempted several times before throughout the years, at least in other Suikoden communities. In fact, I remember auditioning for two separate projects. However, due to people's schedules and life changes, this kind of thing usually never makes it to production.
It's a great idea if you can find people who will commit to the project, though.
But...I don't necessarily agree with simply sticking to the dialogue in-game. As much as I love the stories, I'm not always crazy about the script. Yes, you could leave a lot of lines unchanged, but you would absolutely need to alter some of them, especially in the earlier games. Case in point... everything Pilika says until she gets over being mute, which is halfway through the game. I'm not trying to be funny.
Her lines were painful enough to read in the game- she repeatedly refers to herself in the third person, and omits so many articles that you have to wonder what her first language was. (I have no idea if kids refer to themselves in the third person in other languages, but in English, it's just weird. My guess is they were trying to dumb down the dialogue and maybe overdid it.)
Oh, and don't forget the occasional portrait-swap when two characters are having a conversation. Imagine Lo Wen calling out her own name, Nina declaring her love for Odessa, or Teresa threatening to launch arrows on herself and her party.
But if you're going for a comedy, that's another story...
