Actually, none of that is odd or unexplainable.

Katara's took a little more thought, but it's obvious enough. The last time she fought Azula, the only water available to bend was what was in her waterskin. Which is far from enough to use in all-out combat. Tiny amount of water pitted against someone who can create massive bursts of flame? That'll never end well for the waterbender.

THIS time when she fought Azula, there was plenty of water available; making her able to fight far more effectively using more powerful attacks, forms, and guards.

Also, if you'd been paying attention through the series, Zuko has consistantly been getting stronger and altering his fighting techniques. There was no "magic transformation" (aside from that happy, cheerful attitude....man that creeped me out >.<).

Before, he used the usual "attack with overwhelming force" philosophy that most of the infantry use. Large blasts of flame, and a big opening for the opponent to counter-attack. Not to mention a lot of wasted energy >.>

But through the second season, he started using smaller and more focused blasts; which in all likelihood are much more powerful because all the energy is focused into a smaller point. He's also been developing new techniques for his firebending as well. Remember when he first fought Azula, and he had those wierd little daggers made entirely out of flames? Well that's what the odd fire-whips he used against Katara started as. He also fared much better against Azula the second time they fought; still on the losing end, but he did a much better job of keeping his guard up and trying not to leave an opening for her to exploit.

Also, stop and think for a minute: Zuko's been chasing after Aang and fighting him for HOW long now? Don't you think he'd naturally do better because he's familiar with Aang's fighting style? Especially considering Zuko's been continuously altering and improving his own. Aang on the other hand, seems to be sticking to the basics of each bending style when fighting Zuko.

I agree to an extent, but somethings I also keep in mind are:

A) We only see snippets here and there each episode and therefore do not get to see the amount of time each individual spends practicing his/her bending.

B) The majority of the times we see Katara under-perform are when the only source of water she has is that which she keeps in her waterskin. Conversely, when she has a large source of water nearby, she shines.

I'm not sure if the above are enough to justify all of the seen improvement, but as said before, they are things I keep in mind. LOL

edit: I posted this shortly after Makoto, sorry for the repetition.

Copper for your thoughts.

I think it is because Aang tried not to kill him. I mean, Aang wasn't using his full power at that moment. He just wanted to leave. Besides, Zuko is getting better, but Aang is already a Master Airbender, and is still progressing in Earth and Water. He put up a fight, but Zuko and Aluza were working together to much, and Aang and Katara woulda won if it weren't for the Dei Lei (cannot spell their name) I mean, they were rocking until Aang got knocked off his rock.

Actually that reminds me of something else I noticed.... compare Zuko fighting Aang, to fighting Katara. Anything seem odd? Like, say, the fact that absolutely no potentially lethal attacks were used, and he put very little effort into the attacks he DID use? He kinda seemed at ease and bored when fighting her, and when fighting Aang .... actively trying to beat the bald-headed kid to a bloody, flame-broiled pulp >.>

Yea he just cut the little water thing that Katara had on Azula when he clearly could have taken her out.

I also, agree with the whole we dont see them practicing thing, good point. But, we do need to admit that Zuko was on top of his game and I rather enjoyed it.

It should also be remembered that these shows don't always care about consistancy. That other half-anime show, Teen Titans, certainly doesn't. If you watch the series through you'll see some villains who required all the teen titans to be sudden get paired off with just one and the two are evenly matched.

Its mostly out of convienence that powers are matched up in a show, though I suppose one could look at it as training time between episodes and between the gaps within episodes.