Also remember if kurama hated madara controlling it and treating it like a pet just think how the juubi might feel if you ask me and i could be wrong but i believe that there will be a 2 or 3 way battle for control of the juubi between naruto,obito and madara and ultimately the juubi will choose naruto just like kurama when he said that he would hate to be controlled by madara again and would rather obey naruto.