How can Sasuke try to master his MS if he does not have MS yet? oO

Moreover, Itachi wasn't where Sasuke is now at 6...

People (and Kishi:P) give Sasuke credit cause his potential is blown out to be larger than Itachi's from the very beginning.

What would be the point of Sasuke actually dying on Itachi? Kishi tries to prove that one can surpass his/hers confines so in the end Sasuke wins.

To achieve that he has to be stronger than Itachi, so it's more like some ppl don't give him ENOUGH credit.

It doesn't change the fact he's one cocky bastard of course...