It is probably a touch unfair to examine the first issue of his run, since it is only part of a whole, but I've got a spare fifteen minutes or so, and I was thinking about it anyhow. So I might as well think aloud onto this.
Astonishing X-Men comes at the end of Grant Morrison's run, New X-Men, which I recommend to people. It's a good, solid run, hurt a bit by changing artists early on, but always with a feel that it is heading towards a preplanned end. Which, at the end, shows that it is. One of my favourite things in Morrison's run, however, was the change from spandex costumes to a cool, slick black leather, and a loss of the more misogynistic elements that has plagued American superhero comics for years. It's probably arguable that some of it remained in his portrayal of Emma Frost, but I tend to think otherwise, since she was Morrison's most complex character in his run, and always rose above the revealing costumes she wore. Morrison also brought back many of the old X-Men standards, such as the Phoenix, and the X-Men in the future, so his run was a nice mix of old and new, filtered through a modern narrative style.
Joss Whedon, having written the Fray, a futuristic Buffy the Vampire Slayer comic that started well and ended badly, arrives at the X-Men franchise, the inheritor of what remains from Morrison's run. For him, there is no spandex, the mutant gene will kill humanity off in three to four generations, Jean Grey is dead, Professor Xavier has left, and Scott Summers is in a relationship with Emma Frost...
And evidently, most of this is not to Whedon's liking. Whedon is a fan of the old X-Men, the ones who wore spandex, who would not inherit the world, and who had Wolverine and Cyclops fighting over Jean Grey. I know this, because this is what the first issue is all about: it's about returning to the past, about grabbing the spandex, about claiming that the mutant gene is a virus, about ugly mutant terrorists, and Wolverine and Cyclops fighting over Jean Grey, even though she is dead.
And Emma Frost is, in almost every scene, objectified.
You could say I was disappointed.
I was also, faintly, disappointed in Whedon's characterisation of Kitty Pryde. It's so obviously Buffy Summers that it's not funny--indeed, Kitty is given the same position in Xavier's school for mutants as Buffy was given in Sunnydale High: the link between the kids and the staff, there to help them cope. Yeah, okay, so we haven't seen her do that yet, and maybe he'll do it differently, make something interesting out of it, but please, leave the Buffy thing behind.
This might make it sound like the comic was bad. It wasn't, really. John Cassidy's art was nice, and the story was really an introduction, so perhaps some of my comments will be proved wrong, but... well, next to Morrison's run, Whedon has come up looking merely adequate.