This is a big fat red herring. Miguel hasn't got the charisma to carry the main title.
If it is a red herring, then Dan is certainly laying out plenty of clues to think it might be Miguel. I don;t know if anyone else has spotted this but one of the latest characters in the book is a scientist called Tiberius Stone, one of Miguel's enemies in later revealed to be his fathers was one Tyler Stone. Could the two characters be related, could Tiberius be Tylers ancestor, and seeing that it was revealed in Miguel's book that Tyler was Miguel's dad, he could be the ancestor of Miguel himself? It could be a coincidence with the names, but with Dan Slott's caliber of writing, I tend not to believe in coincidences in the names being similar.