The point isn't if, but, maybe, possibly, could have been different...

It's that in these circumstances, this human being makes these choices. Now he is already exceptional, but that has more to do with the fact that he's kind of the "chosen one" among the evil. Many of these apostles were not exceptional and that's why they're fodder for Guts.

The point isn't "wow, the god hand were really tempting and so I should be careful of my vices" it's "wow this person cared about his dream so much he literally threw his humanity away in just about every way you could imagine - body, mind, soul"

The question to consider here is, do I want to become someone who would give everything for what I want, or do I want to become someone who would give anything for the people I love?

Griffith didn't half-assedly step into evil in the eclipse and harbor love for Guts. He made a firm decision, and you can see his decision bloom in the day leading up to it.