Rigid adherence to canon seems sort of silly to me nowadays. Limiting, even.
Flat out fucking impossible, really; after 70+ years there's just too much shit. Use of canon comes down to deciding what to use, how to use it, and what to ignore. History's a tool, same as any other in the writer's toolbelt.
Now, Mighty Avenger relied on plenty of established Marvel history (mostly in its wonderful use of guest stars), but it's not canon because it rewrites Thor's origin.
(Well, actually, you can of course rewrite a character's origin AND have the new one be canon -- both of the major publishers do it several times a year, actually, from last year's genius "Barry Alan's mom was murdered now" retcon to whatever that Captain America mini that's out right now is called -- but Mighty Avenger is clearly self-contained and has no ramifications for the MU at large. Of course, like I pointed out earlier, you could say the same of Nextwave and X-Statix, so the question of what the fuck canon actually IS is a good one, and should be considered by any nimrods who'd pass up a great book because it doesn't fit within whatever the fuck canon is.)
What was it that Jack Kirby said about stories? It was something to do with ending old stories and telling new ones. Thad quoted it some pages back, I think.
It was in response to a new Captain America artist saying he'd do it "in the Kirby tradition": "The kid doesn't get it. The Kirby tradition is to make a new comic."
In that sense, this new Thor isn't precisely "in the Kirby tradition" because it's an imitation of his work and not something original, but god damn it is a GOOD imitation -- not just of his work at Marvel but of his romance comics, too. It's got that wonderful anyone-can-show-up feeling that the connected Marvel Universe had back before it got bogged down by spoilsports debating what was and wasn't canon, and it's got a sweet emotional core in Thor's relationship to Jane Foster.
Moreover, while I'm all for people creating new books instead of relying on established properties, I think this is one case where it wouldn't have worked. A HUGE part of this book's charm, as I said, comes from Thor meandering his way through the Marvel Universe; it's great fun when Ant-Man, Captain Britain, or, in the final issue, Iron Man in his original armor shows up. This is one of those cases where using original characters, even as obvious analogues, wouldn't have tasted as sweet. (Contrast with my feelings on Mark Waid's Strange mini a year or so back; it was a neat enough little story but I didn't think it gained anything at all by using Stephen Strange as the main character; I felt Waid would have done better to make it a creator-owned book. Sometimes established characters are best, sometimes new ones are, and sometimes using a clear analogue to an existing character actually helps to highlight what's great about the original -- if you were to ask me what my favorite Batman story was, I'd probably say
Confession.)