Alright, but, remember how at some point he said "you can't be hokage like that" ? Then, when Naruto was charging at him with the demon chakra, he was repeating to himself what he had said? I interpret that as him realizing that Naruto isn't what he thought, and possibly a future hokage candidate. Dropout boy, I don't know what to think of that term, because he called Naruto a dropout even after all they both got slammed into the ground. I refuse to think that Neiji is stupid enough to think that Naruto is nothing after all the fireworks. Naruto even called himself a dropout after winning. So I think the term refers to his past performace, and not what he'd shown in the fight. Just so I'm clear about it, I think Neiji's view of Naruto evolved as the fight went on. Everytime Naruto gave Neiji a reason to take him more seriously, Neiji took him more seriously. There wasn't a single time when that wasn't the case in the entire fight. That's why I don't think Neiji underestimated Naruto.