Let us be open-minded and check the whole idea of coming of another Prophet.
All the previous Prophets of God Almighty came to this Earth with some messages which were later polluted by the followers according to their evil desires. Prophet Muhammad (S) came and brought all the true messages in form of Quran which covers all the life pertaining issue well in detail in this book. No need of any other book to support it.
if someone claims He is a Prophet or some on believes that such and such person is a Prophet, we want to know what new message he brought from God Almighty which is not there in Quran.