One of my favorite marvel events was inferno, I wouldn't mind seeing something like that again. Dormammu has been banging on the door of this dimension for too long, or they could use Mephisto. He and Peter Parker having a conversation would be cool.
INFERNO was at heart an X-Men event. It may have involved demons and some tie-ins with other books but it was basically an X-Men crossover. You could do a story about a Snark invasion and it would sell with the X-Men involved.
Marvel made Mystic Arcana about a bunch of random nobodies in the mystical community and withheld the big guns like Dr. Strange, Thor, Ghost Rider, et al. Even with Annihilation, which featured mostly 2nd-stringers, they had enough sense to include the Silver Surfer and Thanos.
Mystical stuff has skirted the edge of the major comics, so there are plenty of mystical characters that a broad audience is aware of at this point. Just bring them all together for an event, is all I'm saying. It doesn't have to be just magic-types involved. Throw the Avengers in to make everyone assume it's relevant to the "main" continuity of the Marvel universe.
Hell, the Skrulls are more of a FF/cosmic villain, yet they were made relevant and profitable by Marvel effectively telling people that they're important because an event centered on them.
Many critics felt Marvel overdid Skrulls and missed their purpose. The Skrulls were supposed to be dangerous because they are shape-shifters, INVASION OF THE BODY SNATCHERS stuff. Instead they fly into Time's Square and stage a frontal assault like basically any alien race from a 1950's B-movie. Their planning was erratic and Bendis explained their motivations better in interviews than in the actual story. One could go on and on. Yes, SECRET INVASION sold, but now the audience is tired of Skrulls. The SKRULL KILL KREW mini has all but sold outside the Top 300 since.
I do agree that MYSTIC ARCANA missed the boat by focusing on C-Listers or no names. As I noted in my above post, though, Marvel rarely learns genuinely constructive lessons from any failure. All they learn is relaunch, relaunch, relaunch. The fact that Joe Q himself dislikes Magic stuff means that Bendis would have to be heavily involved to get it approved, especially after ARCANA...which would mean it would be rubbish.
I see ANNIHILATION and the wonderful Marvel space area as an exception and not the rule. Even that, besides token appearances by Thanos and Silver Surfer (who are in no way large draws either), the original was done by Keith Giffen, who had some name-power. Heck, he still did STAR-LORD for CONQUEST when Abnett & Lanning were starting to feel their way into the universe.
One could say a magic event with Thor as a headliner would at least sell 40k per considering what a draw he has become. The problem is that the simpliest solution is the one Marvel does last; they overcompensate and over complicate; just look at the mess of M-Day. They approached a problem of "too many mutants" and applied a solution that was a creative equal to killing a gnat with napalm and resulting in a book with just as many if not more X-Men in it than in 1997, with a butchered premise to boot. Unless the aim was to turn the X-Men into the New Inhumans, sometimes Joe Q would deny.
The "ASSAULT ON MOUNT OLYMPUS" story out of INCREDIBLE HERCULES is somewhat close, as the gods are "mystical". That's due to involve Herc, the Mighty Avengers, Spider-Man and the Agents of Atlas, at least. That book has been struggling at some 28-31k sales for months, though. It's been faring better than MS. MARVEL some years sales wise, but that isn't a whole lot to hoot about.
I essentially agree that an event, properly hyped, starring Thor alongside some other borderline popular magical heroes like Doctor Strange, Voodoo, Moon Knight, the MI-13 crew, etc. would and could easily deliver sales on par with WAR OF KINGS perhaps. I just don't think Marvel wants to do that right now, and if they do would likely rely on Bendis since some of this spread from NEW AVENGERS, and while he's not in Loeb territory yet (he's pretentious, not dumb, and averages one decent story a year at least), he struggles with everything that isn't solo pulp hero stuff, but sells too well for anyone to tell him so or for him to move along.