Re: Realistically speaking Sasuke has already surpassed Itachi.
I think if itachi were still alive... he would still be able to beat Sasuke. It doesn't matter that Sasuke surpassed Itachi's ocular level, Itachi has mastered his sharingan. Sasuke is really good with his, but hasn't gotten to the level of mastery Itachi has. Plus Itachi always has something up his sleeve, always a new power or plan we didn't know about.
At age 7, Itachi graduated from the Academy at the top of his class after only one year, mastered the Sharingan at age 8, passed the Chūnin Exams at age 10, enrolled in ANBU half a year later and became captain by 13.
So you see... Sasuke at 16 isn't at Itachi's level when he was 13. Add to that the 5 years Itachi has lived more than Sasuke. So you see, Itachi has more feats, more life experience (translates to battle experience), and more powers (Izanami, Kotoamatsukami).
Yes, Itachi died and Sasuke is progressing, which means he will eventually surpass Itachi... but not yet... hey, even Sasuke had to play support for Itachi while Itachi took care of Kabuto.