Guys, guys guys!Hmm, Itachi is way smarter in battle than Sasuke and I'm sure even Sasuke knows this. So he's being smart, for a first, to listen to Itachi. Also, I think he has respect for his older brother.
I never said Itachi is not a smart ninja. But it seems that Sasuke just didnt got any power up and he is giving in to his older brother, even after all he did?!
He killed his parents and all his other relatives. Now he just forgave him ^^