Iron Man 3 was well received by fans for the most part, but there was one issue that seemed to rub a significant number of people the wrong way.
"I'm a people pleaser. Marvel saw so many negative things they made a whole other movie just to apologize called Hail to the King. In which they said, "No, no, the Mandarin is still alive. That wasn't him. There's a real Mandarin." The only reason they made that was an apology to fans who were so angry."
Hail to the King was a Marvel One Shot that followed Actor Trevor Slattery after he was sent to prison. It is revealed that the real Mandarin is upset about the highjacking of his name, and wants to see him. Black goes on to say that initially Marvel wasn't concerned with his portrayal, but things quickly changed, saying: "Of course, they didn't care. But when the blowback hit, they cared."
After being asked why they didn't see the blowback coming, Black responded: "No, we didn't. We didn't know. We all thought they'd eat it up because it never occurred to us the Mandarin is as iconic to people as, say, the Joker in Batman. They just wanted to see the magic rings shoot lasers."
In no way is he as iconic as a Joker or Ultron, and part of the reason they went the direction they did with the character was that the magic elements didn't fit with the movie they were making. "You'd need to take the piss out of it and explain how this can happen. In the comic books, it's literally magic. It's magic from outer space. I love the fans. I really want to please them."