Nah, Aang was annoying with his whining.
Hell no. I don't believe that for a second. Ozai was already ridiculously powerful, without the comet, and with it, he became an absolute juggernaut. He was pretty much curb-stomping Aang.
We know Aang could have won simply due to lightning redirection. Putting that to the side for the moment, though, I think that it has to be remembered that he wasn't actively trying to win and wasn't even really making semi-full use of his abilities. He was chucking medium-sized rocks in Ozai's general direction (and never directly at him) and occasionally bending a stream of water towards him. You're probably right that he couldn't have won short of lightning redirection, but I think a good deal of the curb-stomping appearance of the fight stems from Aang's approach to it (and I think the DVD commentary bears that point of view out).