Until now, you must have heard that Age of Ultron's Blu-ray will feature both a director's cut as well as an alternate-ending. While we still don't know anything about the extra scenes that might be featured, we do know how the movie could have ended - Joss Whedon, in an interview with Empire, revealed what that ending presumes.
So if you are in for some spoilers, then check this one out - if this version ends up as canon, then your perspective of Age of Ultron and the entire MCU will change.
Spoilers ahead
We all know that, at the end of Age of Ultron the new team is presented - War Machine, Black Widow, Falcon, Scarlet Witch, all under Captain America's command. And we all know that Quicksilver ends up dead, after saving Hawkeye. But was it so?
Here is what Joss Whedon says: "We did actually shoot him in the last scene, in an outfit, with his sister. We also shot him, waking up, saying, ‘Ah, I didn't really die from these 47 bullet wounds!’ Actually, we shot something else with that, but… maybe I'll let you know about that later. But the intent was to earn this, and then you have to stand by it."
So nobody died in Age of Ultron
In a way, this alternate ending of Age of Ultron meant that no Avenger (or some other important character, other than Ultron) has died in the movie. In this way, this meant that the threat of the powerful AI was diminished - and seeing that Ultron wasn't as frightening and powerful as we thought prior to the movie's release, then this wouldn't have been quite a good idea.
While Joss Whedon might have approached Quicksilver in a different way, having him dying in Age of Ultron was actually a good thing. So the question is: will the alternate ending of Age of Ultron become canon? Because we really wouldn't want that.