It's becoming increasingly clear that Joss Whedon's run on Astonishing X-Men is just a big 'ole love letter to Chris Claremont and Grant Morrison. This is, of course, both a good and a bad thing.
Note, for instance, how this 12 issue mega-arc continues to unfold like the Dark Phoenix Saga, though with a twist: where Emma Frost occupied Jean Grey's role during "Torn", Colossus has now become the Phoenix-figure who will wreak massive destruction. Like Jean and Scott, it's Peter and Kitty who are all alone in a hostile environment against an alien force bent on killing them. And again like Jean, Colossus is starting to believe that he's capable of the mass genocide that has been predicted. It's also becoming increasingly clear that Whedon was never sincere in advocating a return to the costumes and superheroics that Cyclops suggested in his first issue. If issue seven wasn't enough to confirm that the X-Men would never really be accepted as heroes, then Whedon's gradual destruction and removal of Cassaday's superhero-outfits seem to speak more subtly and undeniably to this goal: Cyclops eschewed his Cassaday-look for Quitely's leather jacket during "Torn" and now Wolverine's costume has been incinerated, leaving both mask-less as they were during Morrison and Quitely's New X-Men. Even Kitty's costume is starting to look more like Quitely's designs to my eye.
There's little new that I can add about Whedon's dialogue or Cassaday's art, as they're consistently fantastic. The only remarkable blunder - and it's a big one - is the final page reveal, which has been an unfailing strength of this creative team throughout their 20 issues. The punch-line to Kitty's unintentional joke that Colossus' future is not "written in stone" is a 100 foot-tall artwork in stone of Colossus destroying the Breakworld. It's a cute ironic gag, but it makes absolutely no sense. Located underground by Agent Brand and looking quite old, it defies all logic that this prophetic picture would be anywhere on the Breakworld - after all, the Breakworld aliens only learned that Colossus would destroy their world from Brand herself, didn't they?
One last note on Whedon/Cassaday's run as a whole and this issue's place in it: It's telling, I think, that every storyline has moved further and further from the conceit of mutant-politics that featured so prominently in the initial story arc. While "Danger" looked at mutancy of a different sort, "Torn" had little to say about mutants and less to say about their oppression. Thus far, "Unstoppable" is another in a long tradition of X-Men space adventures that have absolutely nothing to do with being mutant - though through its intimate connection to an anxiety of influence with regard to previous X-tales and their creators, it has absolutely everything to do with being X-Men.
Exactly what it means to be X-Men outside of being mutant activists and/or not being real superheroes, well, I'm not entirely sure what Whedon is suggesting. The problem with love letters is that what or who they're about is always itself absent. It might be described beautifully or provocatively, but you can only see glimpses of the loved object from a distance.