Yes I believe Orochimaru will be the final villain and not Madara. He's always been the villain in Naruto so I see him being the final villain as well. He is extremely underrated because he lost to the third, but even the third is extremely underrated. Orochimaru most likely knew 1000+ jutsu's all of immense caliber. He knows more about clans and villages than then anyone in the entire series, he has more intel on any clan as well due to all the tests he has carried out. He does not die and has amazing summonings which include Snakes and edo tensei. He would most likely have put up a much better fight against Itachi if he knew he had the totsuka sword and didn't expect it at all. Orochimaru is stronger than Jiraya and Tsunade and both are Kage level shinobi. He is a complete shinobi except for having uchiha eyes, which is why he needs them so badly. He does not die and can revive through curse marks once the user has depleted their chakra completely, he had a immense arsenal of jutsu's before he fought the third and still has one filled with kinjutsu, he can change bodies and most likely has many blood line limits due to all the tests he has done, he has great summonings and uses edo tensei, and finally he is the most knowledgeable shinobi in Naruto. If he gets a sharingan he would be to OP, and if anyone believes that he is not a complete shinobi then he is retarded. He is too underrated in my opinion.