Don't dismiss this hypothesis.

1. Kimimaro was the strongest in his village (potential Hokage).
2. With Kimimaro's body they could have more easily vanquished Konoha.
3. Kimimaro was also an heir to a clan that posses the most perfect and most powerful bodies of all; and inherited all their abilities (Blood Line limit).
4. Oro prefered Kimimaro over Sasuke, but when Kimimaro became ill, Oro needed to find another Host. Sasuke is simply, sloppy seconds.
5. We don't know how strong Itachi is. I know everyones going to say he beat, blah, blah, blah, blah, blah. Basically, he basically gave the jounins a hard time (jounins that Kabuto could have given a hard time), and he ran away from Jaraiya. If that's enough evidence for some of you folks then, that's okay. But for me he needs to prove himself a little more. Time will tell how tough he really is.


That's my two cents.