Flip Flop of God: More or less what All Hail the King was: Marvel and Iron Man 3 co-writer Drew Pearce deciding to backtrack on The Reveal of Iron Man 3 about The Mandarin by revealing that neither Trevor nor Aldrich Killian were the Mandarin, after director Shane Black said in both an interview and on the commentary that Aldrich was the actual MCU incarnation of the Mandarin. To be fair, Drew Pearce has admitted that he had the idea about the real Mandarin in mind while writing the movie, but that Shane Black was not privy to this information since it had little importance to the movie.
Among the proposals for shorts were stories featuring Jessica Jones, Damage Control, and the supervillains Sin and Crossbones. Jessica has since gotten a series on Netflix, and Crossbones appeared in The Winter Soldier.
The Stinger of Agent Carter with Dum-Dum Dugan had to be changed from him being in the pool to sitting by it, because the muscle suit Neal McDonough wore wasn't waterproof.