Originally Posted by Ksb36
The filmakers clearly don't want to be boxed in, committed to one storyline when they don't even know quite how they want to get a character to a certain point. They may know the end they want to achieve, but at the time the Avengers filmed, there may have been discussion about how much of Cap's past they wanted to address in an ensemble piece.
My best guess is that due to the tragic nature of Cap's lost love, they didn't want to settle that plot point until he was in his own story. The Cap/Peggy romance was the best one in the Marvel cinematic universe, so far (although I do really like Tony/Pepper) and they want to give it the weight it deserves. So, NO, in my opinion, this scene, while nicely done, is not yet cannon.
I'm all for romance in the MCU, especially for the 93-Year Old Virgin, but some of you are grossly overrating the Peggy thing. "Best one in the MCU....?" Hardly. They only kissed once, and that was nothing more than a Leia-style "for luck." And as for the comic book canon: we're in uncharted territory regarding Peggy now. In 616, there was only 20 years removed from WWII to Cap's unthawing, so Peg was still very much alive, very much an active SHIELD agent, and very much a hungry cougar still after young Steve. Not possible in the MCU, when 70 years (and possibly death) separates them.
Tony-Pepper, Thor-Jane, Bruce-Betty, and even Widow-Hawkeye have more romantic development and potential in the MCU than Steve-Peggy ever did. The only romance there at all is just a promise that was never fulfilled. Poetic and tragic, but *not* romantic.