They're not calling her Sharon Carter in the press release because, in the comics, Agent 13 was a mysterious figure who we didn't know who the heck was. I'm assuming they're keeping this element in the film, by having her as an undercover operative.
Also, I'm guessing the main conflict in the film will be stopping Winter Soldier from carrying out an assassination on a prominent politician or stopping a terrorist attack. So they don't need Zemo or Strucker at the forefront for that. They could reveal they were behind it all at the end...which I think someone brought up a couple days ago.
Originally Posted by HighFivingMF
I'm pretty certain The Dark World has at least one, if not two.
No, there really aren't any.