Well, if that's what it's about, the only reason I can think of for people calling the MC weak is that we've never seen the MC being OP in any fight. Even with the Golden Seed, which is supposed to compensate for his lack of experience, he still struggles.
Another thing is that the power scale in Poma has never been clearly defined—or at least, that's how it feels to me. I used to think that 10k stats were what most PH geniuses had, but now I believe it's even higher, considering that even with Asura, you can't defeat a group of five people. Supposedly, it's the most powerful art in that world, and when combined with the Golden Seed, it should have been a battle he was meant to win, but we all saw how that turned out.