Godlike
Reicher (Mana Khemia 2: Fall of Alchemy) vs Apocrypha (Radiant Historia): Very strong kneejerk. Reicher's offence just feels way, way better, and I can't imagine their durability is that different.
Fou-lu (Breath of Fire IV) vs Lady (Shadow Hearts: From the New World): This is close. If Fou-Lu 2HKOs - and he probably does - then Lady only gets two turns plus her death counter. Still, that's enough for 3.2 PCHP damage, which I think takes Fou-Lu down. There's certainly an argument that Fou 2HKOs and tanks the two Lady turns, but it does need both calls.
Velna (Legaia 2: Duel Saga) vs Dragon Emperor (Seiken Densetsu 3): Can hit both defences and has oodles of stat downs so I don't think it really matters what sort of credit or interps you give Velna here.
Heavy
Margulis (Xenosaga Series) vs Kary (Final Fantasy): Margulis is all elemental or physical, neither of which works well against Kary. Halved Raktas are the best bet (but that's below half HP only!), but I don't think it's enough with Kary hitting the right defensive stat and all, even if evade makes it open to discussion.
Chocobo Eater (Final Fantasy X) vs Rufus (Valkyrie Profile 2: Silmeria): VP's melee fighters are either light melee, heavy melee, or ranged... all of which have perfect analogs in FFX. Wakka's not piercing, so I don't see Rufus as piercing, ITD or no (FFX certainly has examples of ITD non-piercing weapons, such as celestials). That settles that. (Chocobo Eater might even win this even if you take the other call, but I'm not mathing that out.)
Oerba Dia Vanille (Final Fantasy XIII) vs Oerba Yun Fang (Final Fantasy XIII): They're both kinda firing status at each other immediately? Fang wants to land Fog which leaves Vanille utterly wretched, Vanille... actually, is in a much worse boat because she really needs to land both. With just Pain, Fang will just Fog her back. With just Fog, Fang still has good physicals. I mean yeah Vanille may get lucky, but especially if Fang has Improved Debilitation, the odds are just in her favour.
Middle
Dekar (Lufia 2: Rise of the Sinistrals) vs Seifer Almasy (Final Fantasy VIII): Yup
Rudy Roughknight (Wild ARMs) vs Roxis Rosenkrantz (Mana Khemia: Alchemists of Al Revis): ACF Rudy certainly OHKOs Roxis, yeah; he hits harder than I thought. WA1o only 2HKOs, and since he's slow, Roxis should be able to get off enough Chrona Drive + a finishing Trick Edge to go a little past a KO. Buuut... I feel I should probably vote on WA1o. As a group, Rudy/Jack/Cecilia definitely prefer that, as Rudy gets only somewhat worse while the other two get a lot better, and I'm not one to let the characters pick and choose and cheat averages.
Silmeria (Valkyrie Profile 2: Silmeria) vs Paws (Cthulhu Saves the World): Well Paws hates both silence and stone so pretty sure he's just screwed there.
Light
Algus Sadalfas (Final Fantasy Tactics) vs Andre (Shadow Hearts: Covenant): Hmm. Algus goes first, but Andre lands blind on his first attack and thus odds are one of Algus' next two attacks will miss. So Algus needs to 2HKO. Which he... may? I have a hard time reading SH2 bosses. Andre is certainly more fragile than Lenny, but should compare reasonably well to Veronica/Rasputin. I dunno. And of course there's a chance Algus wins even if he only 3HKOs (blind fails)... but also a chance Andre wins if he's 2HKOed (blind is awesome). Abstain for now, I'll let others make this call.
Racially Insensitive Wizard (Final Fantasy) vs Cinnamon (Mega Man X: Command Mission): Faster and 2HKOs. This is kind of a slaughter.
Garcia (Fire Emblem: The Sacred Stones) vs Rafa Galthana (Final Fantasy Tactics): Even two doubled Rafa stick beats don't take down Garcia (they do 1.17, he has 1.25 pdur), and he can probably kill her with opening Hand Axe counter + Silver Axe (and gets two shots of the latter, so evade isn't tilting this). So... yeah, she's going for Truth to keep her alive. I don't see this doubling (or triggering counters), as mentioned. Truth 5HKOs but can it keep Rafa alive long enough? Yeah, I... can't really see it happening, Truth heals like a third of average PCHP so Garcia blasts past that pretty effectively, Rafa's only chance is to get lucky with some evade I have a lot of trouble respecting (and I'm really surprised Dhyer does, no shield = below average!)
Sazh Katzroy (Final Fantasy XIII) vs Piccolo (Suikoden III): Sazh can barely stave off a 2HKO with Barthunder+Shell. So... open with Haste+Barthunder, Shell+Brave? That gives Sazh... just one turn to finish off Piccolo with. And even with Brave, I don't think Piccolo is -that- frail.