maybe kakashi is half uchiha(soeculation), i really think Kakashi's past will be revealed sooner or later because i have this feeling that the manga will last for another 200 chapters atleast i hope, we also need to know more about Gai's past, Kabuto's eyes (bloodline limit??) the 4th's connection to Naruto (possible father) etc Naruto is full of unexplained things this is what makes it such a good story because as the story progresses we learn more and more about the charachters so I really hope Kishimoto will give them all a past that fits in the story