This thread had me worried with those renderings. Thought they were real for a second.
What's more realistic to me is that Silverstein might want to take Foster's design and maximize the possible square footage out of the existing footprint. Perhaps by taking a page out of the BIG design and adding setbacks to the western portion of the tower. Something like this:
Nixing the four diamonds or modifying the height seems too far out of the question, and I don't think Foster would want to see something like that happen to his baby.