Making the public believe Hawkeye was going to kick the bucket was Whedon’s intent: “I wanted them to announce Aaron Taylor-Johnson’s nine picture deal, and for them not to announce Jeremy was going to be in the next movie, and all that good stuff. […] But it felt very disingenuous for meâ€.
However, he played that card in the movie. A lot, especially in the Barton family house scene: “I would say, ‘Let’s have a shot of him looking at a picture of his family!’ Then, ‘Tony should say, “One of us is definitely going to die!”‘ And I’d laugh and laughâ€.
As to his decision to sacrifice Quicksilver, well, Joss Whedon puts it like this: “I said to Aaron, ‘The only way you’ll stay alive is if the Disney executives say, “Hey idiot, this is a franchise, and we need all these people and you’re not allowed to kill them off!”â€.
In a way, Whedon did save Quicksilver. Of course, in the alternate ending we elaborated on here. But on the big screen, the director had his ways, unstopped by any of the Marvel higher-ups.
3. On Thor’s dream

Basically, the Asgardian’s vision should have been longer. Long enough to include Loki too, but not only. We explained here why Joss Whedon was pushed to ax the Loki scene.
And to think he did that after he personally sat with Tom Hiddleston to talk him into reprising his role! “And then I talked to Tom, saying, ‘Just so you know, I feel bad not telling you, and I would never pressure you, but… I really feel like it would be great if you could do this…”â€.
Now a new detail is spilled out:
