To which I say: Give me a break.
Of course they'll all be returning for the next film.
As of the time I'm writing this Iron Man has grossed close to $400 MILLION worldwide in just THREE weeks. And of that doesn't include one penny from all the movie tie-ins from deals with Burger King, toys, t-shirts, etc., etc.
Does anyone seriously think that Marvel and/or Paramount is going to mess with the formula that generated those numbers? I think not.
Iron Man 2 already has a release date set: April 30th 2010, but apparently the first Favreau heard about it was via the press release. People are taking this quote from and interview at EW and are running with it:
"Will you be involved with the sequel?"
"We've been speaking informally about it, and in concept we would all love to work together again. But I found out about the announcement last night, so it's not something that — we would definitely love to collaborate more with the sequel. There's no formal arrangement yet, but in theory we would all love to see it happen.... There's definitely a lot of ideas that we all have now. This type of movie is based on serialized materials, so it lends itself very easily to [many different sequel possibilities]. There's definitely a level of enthusiasm from myself and the cast to tell more stories."
Then comes some info via /Film from an interview of "Favs" by Howard Stern where he revealed that he was paid $4MM to direct the film and has a revenue sharing deal based on the movies NET profit (this is an infamously bad way to go as the books can be "cooked" to make the most successful film look like it never recouped its costs).
There's also the fact that Favreau has mentioned the "Demon in a Bottle" story from the comics, where Tony Stark spirals into full blown alcoholism and loses everything, and whether the studio thinks that would be an appropriate direction to take.
The conclusion being drawn from this is that he might not return and someone else may take over the reins of the burgeoning franchise - To which I say: Bull!
In one of my interviews with Jon Favreau the "Demon in a Bottle" story came up as a point of discussion and he was fully aware of what a delicate balancing act it would be to use that story in one of the movies. He's aware that Paramount / Marvel want to be able to market this movie to families and that it would be a tough story to tell (or sell to the studio) within the confines of a family-friendly superhero movie.
Will the alcoholism story actually make it into one of the movies? At this point that's up in the air - heck there isn't even a script for the next movie written yet as far as I know. But I do know this: Favreau knows where he wants to take the story over the course of the next couple of movies even if the specifics aren't mapped out yet.
So while details may yet need to be worked out, I have NO doubt who will be directing the next kick-ass Iron Man movie: Jon Favreau.