Auron's fault?

[Pete for President]

Throwing my lot in with Goldenboko too.

As for the actual question, I'd say Auron has an impact on Tidus, for sure. You notice that Tidus says "This is my story" during the game and is met with a bit of a frosty response; he doesn't realise that it's not just about him, which is a stark difference from his celebrity life in Zanarkand. But Auron, being that sagely bastard that he is, allows Tidus to become arrogant, and the fact Auron is a big deal in Spira doesn't help either.

But Auron knows that Tidus being arrogant is the least that matters in the whole plan. Sin needs to be destroyed no matter what, and arrogance is somewhat related to confidence.

As for the main question; no, it's not Auron's fault. Joining in with Goldenboko's quotes, there is nothing 'faulty' about Tidus (side the laugh scene, but enough of that).