That is purely a myth and marketing strategy. He has not dropped everyone he's faced as claimed. http://boxrec.com/list_bouts.php?human_id=257314&cat=boxer You can even see by the judges scores of some of his UDs that he didn't drop all of these guys.
Boxrec does not list all knockdowns unless confirmed-with that said everytime I've seen Ortiz, he scored a KD (minus Floyd).
Feint and power I agree with but it wasn't a very fast punch. It was a punch Floyd would've saw coming if not for the feint. Mosley's speed has declined considerable while Cotto's average speed has remained the same.
Just look at all of the scores of Ortiz UDs and you will see there were fights where he didn't get a knockdown.
Everyone has a "chance" but Cotto's are slim. He's going to have to fight the most intelligent fight of his life. If he can get some of his lefts into Mayweathers body, things could get real interesting. Mayweather is tougher than most give him credit for. Not only that but he is a master at making adjustments, and it will be very difficult to implement a gameplan against him. Cotto will have to make his adjustments as well to remain competitive. I can see Mayweather winning a comfortable UD.