"'The Avengers' had no studio tinkering. It only had studio helping, which is a very strange position to be in."

Everyone in the cast makes Shakespeare appear effortless -- no mean feat.

It's very important. If it doesn't sound contemporary, then the distance between it and the audience is going to be insurmountable. And the fact is, the language is fun to say. It is lovely to speak it, and to hear it said. I think, nobody was better than Kenneth Branagh at taking this endless paragraph that you read as a kid, and then speaking it as though it was the next thing he was speaking and you understood it perfectly. That's what you need, and all of these actors are so facile with it, and it comes so naturally to them, either because they've done it a million times.

Read More of Indiewire's Extensive Toronto Film Festival Coverage

Nathan Fillion's done some at our house for readings, and that was it. He was a nervous kitten. But you can't tell that he hasn't been speaking it all the time. And that has to do with my knowing of their precision with their instrument. I mean, not to sound like a pretentious guy, but there are actors I love whose control over their voices is not so specific. And you really need that.

"The Avengers" and "Much Ado," while totally dissimilar for obvious reasons, play the same way -- they go by like a breeze. How do you achieve that quality in your work?

Well, "The Avengers" had no studio tinkering. It only had studio helping, which is a very strange position to be in. They had parameters, and that's the best way to work -- to get people that are up front about their parameters. When you get people that are going to change them halfway through, you're gonna be in trouble. And that's happened to me. But when you have people that know what they want, and you're like, "Good. This is what you want, here's what I want. Here's how they mesh. You all agree?" And then that's what you pursue, you're in a good position. Like "Much Ado," "The Avengers" was a movie that I got to make the way I hoped to, from start to finish.

Joss Whedon Mark Ruffalo The Avengers

This probably sounds redundant, but how overjoyed are you with the success of "The Avengers"?

You know, it's lovely. I like a big round number. For years I've only said, "Look, trust me and I will make you money." I have respect for the business, for the fact that these people have made a great investment in me. But sometimes people make a great investment in you, and still not give you that trust. And then you can't, and then they cancel "Firefly." [laughs] And then for them to give me that much trust, and that much support, and for it to work for them and me and the audience -- for it to tap something because clearly it's greater than some of its parts.

You know, it's not a perfect film, but it seems to have tapped into a need, and that's more exciting then -- making a perfect little jewel. It's just hitting somebody in the gut, in a nice way. Kissing them in the gut? No, that sounds awful. But I have to say, there is not a number that can make me feel the way I felt during the screening of this, of "Much Ado," when the audience all got on their feet at the end. And I'm not saying I might have shed a tear, it's probably something I ate.

Congratulations on your return back to television with the ABC pilot pickup for "S.H.I.E.L.D."

Thank you.

Update me on the progess of that and of "Avengers 2"?

There's been enormous progress. We are trundling along, I can't share much. And by much I mean anything. I can say that "S.H.I.E.L.D" came together in a very organic way. And part of my taking "Avengers 2" was that I'd have the opportunity to work in the Marvel universe. I didn't exactly know I'd be running a TV show five minutes later.

On top of your commitment to Bellwether...

Yeah, but it's something I really believe in. Although,"Avengers" is the top of my list of exciting new things, "S.H.I.E.L.D." is really talking to me.