Consider this. They want to do like they did with the original movie and take the idea and do their take on it. What I have read is the took his proposal, went 'mmmthanksbye.'. And made their own movie.
And they are doing it again, despite the fact it would make more money working off of Joss and company doing it.
Given the fact that he still owes then, what... Another show by contract, wouldn't it be good to work WITH him?
This all makes sense, and I don't really disagree. But I think it's worth mentioning that because of the way TV shows are put together, with many people sharing responsibility for basic decisions, it's impossible to say for certain how many of Whedon's successes were due to his own work, and how many resulted from other people's input, perhaps even input from the dreaded executives.
You could say the same thing about George Lucas and the six Star Wars films. Like Whedon's TV shows, those movies vary so widely in terms of overall quality that it makes it hard to believe the same person was responsible for all of them. And if in fact there were many guiding hands behind those projects, who knows what Whedon or Lucas actually did? For all we know, they might have been directly responsible for the worst stuff in both franchises, and in my opinion, there's so much bad material in both franchises that neither Lucas nor Whedon should be exempt from criticism.
Their celebrity status puts them above reproach in the minds of many fans, and maybe those fans are right; I'd like to believe that too. It's much easier to scapegoat the anonymous executives for all the mistakes, but the true picture is probably far more complicated. I would not be surprised at all, for example, if one or two of Whedon's usual collaborators (co-producers, co-writers, etc.) are actually responsible for much of the best work that he's gotten credit for.
It isn't inconceivable
that there could be a faceless collaborator or two -- perhaps even executives -- behind all
of Whedon's best work, except maybe the stuff he has sole credit for ... but most of that stuff is writing, and Hollywood's union rules make writing credits completely untrustworthy.