Ok right now the candidates are: Kakashi, Shikamaru and Naruto.
Shikamaru would be a great leader, with his high intellect he can make the best decisions for the village. On the other hand the hokage has the roll to protect the village, something i doubt Shikamaru is able to do.
Naruto... well it's easy, he loves the village very much and would risk his life any time in order to save it. He also has the necessary skills to protect everyone. BUT he wouldn't be a great leader, he has no experience in leading other people, he is more of a one man team... I think that he will grow up in this war and develop leading skills, and acquire everything he needs in order to become the greatest hokage.
And finally Kakashi.... well he is basically a mix between the previous two, but does not surpass either of them. What would make kakashi a great hokage is his experience, something the young ones still don't have.