5 mistakes in Naruto, that could've change the whole story

[Conspirator.]

1 - Why didn't Kakashi send a Kage Bunshin in Kamui Land just for info?

I fail to see how this would help. Care to elaborate?

2 - Why didn't Itachi Totsuka Blitz Kasime, just to get rid of him? Then Totusuka Blitz pain? (He was a double agent)

Because he was a brutal and genocidal maniac who did everything he could to destroy the world. Mainly by helping Akatsuki obtain nukes-and he did nothing to stop it. I mean, look at Kakuzu as an example.

3 - Why didn't Itachi conceive the Uchiha to move to a different village?

No point. Why would the clan want to leave the village? Not like Itachi would be able to convince them anyway/

4 - Why did Jman wright the code in the frog instead of just writing it regularly & saving time?

He was probably playing it safe. Just in case Pain(or someone close to him) somehow found out what information Jiraiya found.

- Why didn't Tobi Capture Naruto when he was right at front of him? ( 5kage summit arc)

Why didn't Tobi capture Naruto when he was a kid? Lol. But in all seriousness, he probably wanted to start the war before capturing the 9 tails(which needs to be sealed last). Plus, by capturing Naruto, more people would be after him.