Not combining agent Romanoff with either Hawkeye or Captain America was a good call: "The Steve thing, I'm sort of like, ‘I don't think that was ever going to happen.’ That was never their intent. ["¦] The Clint thing, I have a strong opinion about. I think they're wrong."
More about "the Clint thing": "I think it's wrong to assume a romance. It's much more not only interesting and useful but actually romantic that there are these two people who would die for each other, who are not sleeping together".
Clearly, Joss Whedon counted on the element of surprise: "for me, just to go to the sexy romance place is, I think, the obvious choice and not as interesting a message".
Plus, there is a similarity between Banner and Romanoff that supports their romantic attempt: "I felt that they both have this outsider thing. They're really the two who cannot refer to themselves as heroes, even if they are. Neither of them has powers".
No, don't jump to conclusions. Joss Whedon explains: "When the Hulk shows up, Bruce is gone. Natasha is extraordinarily well-trained, but she doesn't actually have superpowers. They're ordinary Joes in a way. Yet they've both lived completely outside of normal society for most of their adult lives, and in her case her whole life".
Some of the scenes between the Natasha and Banner were cut. But they're going to be on the DVD, as Whedon reassures us "“ all the more reason to buy it. Including one moment when Banner rejects Natasha in the bedroom scene, described by Whedon as "some of the most beautiful stuff and I hated to cut it".
They decided to ax that and leave the rejection to the end of the movie.
2. On the long-rumored kill of the installment
Joss Whedon was as devious as he could in respect to this particular aspect. Sure, the fact someone had to die was pretty obvious: "I know I've got this reputation, and some people were going to say, ‘There he goes, again with the killing!‘"
It was only in late March that rumors narrowed it down to Quicksilver. But before that, all theories were equally valid, including the death of Hawkeye.
Which is exactly what Joss Whedon planned.
