What is so bizarre about a console manufacturer paying a publisher to get some extra content made exclusively for that platform (particularly if it's going to be exclusive for that long)? I mean, who knows, maybe they did just choose some already-existing content to be exclusive, but I don't find it that crazy a situation personally.
That is the way i see it happening. It cannot be core to the game since not all version will get it day one. It has to be extra stuff...