Comic-Con takes place just a week before the release of Ant-Man. Why Marvel wouldn't take the opportunity to give it a last-minute push is hard to say. Edgar Wright's departure was a massive blow to fans, and despite how well-received recent trailers for the movie have been, Marvel still needs to restore some of that lost faith to ensure they can add it to their long list of hits. Even so, not hosting a panel means that they can't even repeat a tactic which worked well for them last year. That was a recorded message of Guardians of the Galaxy director James Gunn showing off some new footage from the movie and announcing the release date of a sequel a few weeks before the first instalment was set to reach cinemas. Box office analysts would later argue that that show of faith from Marvel may have helped Guardians of the Galaxy to find the success it did. With Ant-Man also deemed a "risky" move on Marvel's part by some, one final Hall H panel really could have helped them, as would have confirmation of a sequel (a sure sign of confidence in the movie from Marvel). There have been a few rumours about Marvel screening the movie in San Diego which make some sense, but that's not exactly an idea which they've put a great deal of effort into thinking up! Providing the movie is good, Marvel will benefit from the positive buzz which comes out of that rumoured screening, but it pales in comparison to the kind of buzz a Hall H panel can provide.