Sure the man can write, but his work is almost entirely in the realm of tv, and this is supposed to be a huge blockbuster with special effects after special effects.
? Aside from a few guest directing gigs on TV, nearly every project he's touched this side of 1992 has featured SFX in at least some capacity, sometimes in a very large one. Joss is no stranger to special effects; he's just never had this many tens of millions of dollars to spend on them.
Yes, but they had a good deal of directing experience. Whedon directed some of his tv shows (not many considering using an imdb search) and one movie.
Have you seen them all? Because I have, and they're quite good. "The Body" is one of the most powerful episodes of television I've ever seen—an episode which features an Avengers comic reference, no less. But "Prophecy Girl", "Innocence", "Becoming", "Amends", "Hush", "The Gift", "Once More, with Feeling", "Chosen", "A Hole in the World", "Serenity", "Objects in Space"... all fantastic episodes he both wrote and directed.
He's produced 15 seasons of television over the last 14 years. But he's also been writing films for two decades; his own scripts aside, he worked as a script doctor on a number of films you don't see on IMDb, like Speed
. (Side note: Here's a great interview
where he talks about some of these, like X-Men
Oh, and he's written comic books. Including Marvel comic books.
I think he'll do just fine.