You're right. Sasuke could not kill him. He could not bring himself to kill his friend. If however, you mean Sasuke did not have the ability to kill naruto, you're dead wrong. Naruto was on the floor, unconscious when the fight ended, Sasuke walked away. Not to mention, Sasuke outpowered Naruto's rasengan with his chidori at the end of the fight. If you're talking skills and not power, Sasuke succeeded in pulling off 2 finishing moves on Naruto, both of which would've ended anyone without demonic enhancements.

Where do you get Sasuke having the same disadvantages as Naruto? They're extra power sources are different, so it stands to reason that they're advantages and disadvantages would be different. We really don't know much about Sasuke's powers at all.

I hate it as much as you do, but from what we've seen, Sasuke has Naruto trumped. We need more information about Sasuke in order to determine what MIGHT happen in a future fight.