Originally Posted by
Theodric
To be fair he wouldn't have hit a wall for quite some time, though. Bear in mind that that game exists in a weird time bubble and so although a lot of time has passed in the real world it hasn't been that long since the Warrior of Light first arrived in Gridania/Ul'dah/Limsa. I don't deny that the Warrior of Light has accomplished a lot but he still doesn't know everything there is to know about battle.
I'd also point out that Sin Eaters come in quite a vast number of varieties, each needing to be dealt with differently. To say nothing of the various other threats present across Norvrandt. In addition, simply being wounded by a Sin Eater is often enough to condemn someone to the unfortunate fate of either turning into one instantly or slowly devolving into one over time.
So I took it as him being a powerful foe by virtue of living and surviving long enough to outlast many others. Much like the Warrior of Light, Ran'jit lost a lot of people he presumably cared for. Friends, family, the various 'Minfilia' girls, comrades and so on.
One might even argue that some of those we face have lost far more than the Warrior of Light and as such something breaks in them that cannot be repaired. Yet they still have that drive to push onwards, further fueling their ability to fight.
That's how I see it, at least.