There is a common misconception among players of Suikoden 2 that raw stats make or break a character. They see Pesmerga's, Georg's, or Humphrey's large amount of STR and assume that they're the most powerful characters available. On the outside, it looks true, but let's look further into the battle system.
We'll use Pesmerga and Hai Yo as examples. Hai Yo is really an underused character who doesn't get the credit in battle he deserves. For the purposes of this essay, we will assume that they are both at Lv. 99, weapons sharpened to Lv. 16, and their stats are at their highest possible levels (without magic stones). We'll also give them the most armor and accessories that can boost their STR stat.
If you're wondering where we got all those Power Rings, here's a list of where they can be found. One is equipped on Long Chan Chan, one is in the Sajah Rune Shop, one from the Guardian Deity event, and one in Tinto.
Pesmerga's damage formula is as follows.
1.5(255 + 160 + 20) x 2 = 1305 (652.5 or 653 per hit)
Hai Yo's damage formula, however, is this.
1.5 x 1.5(165 + 165 + 60 + 15) x 2 = 1823 (911.25 or 911 per hit)
Hai Yo deals 513 more DMG per turn than Pesmerga. Add in the fact that with his Killer rune, Hai Yo has more of a chance to deal a critical hit than Pesmerga. To find the actual damage done, simply subtract the enemy's PROT stat from each hit.
So there you have it. With some customizing, even Hai Yo can be a better fighter than Pesmerga. It's all because of his customizability and rune slots, not because of raw stats.