Agreed, but I don't think there will be a new trailer. Maybe a single scene which won't be released to the public. I think alot will be announced but most of it will end up in the public sphere. I'm sure some of the bigger "nerd news" sites will have people there to cover the event.
Have to keep in mind Sony needs this movie desperately. Even before the email hack, Sony has been in the red with their entertainment division for years. Without Pascal or Feig, I feel like Aykroyd and Reitman for better or worse have more creative control. Sony knows Ghostbusters is one of the few IPs they own lock, stock, and barrel. They aren't just pushing GB because of nostalgia, it's also because they are running out of options. Venom was a pretty nice boon for them but they still have to split part of that with Marvel. GB and Men in Black are being redone because Sony needs a big win for an in-house brand.
The most ironic thing is, I think the less-than-successful 2016 reboot will end up being a blessing in disguise so to speak. I'm not bashing the movie or going off topic, merely pointing out the objective fact that Sony didn't foot the bill for that movie to come in second opening weekend and have a massive drop-off and end up losing 70-100 million. But I think it will help them avoid the pitfalls Feig's movie fell into. (And this is an opinion but Jason Reitman is a far more capeable and talented director than Feig)
The best thing about all of this is that we really have no idea what to expect and that's so exciting. Reitman has never helmed a project with the kind of commercial potential as this. For a while, I'd been championing someone like Edgar Wright or Taika Waititi to direct a new Ghostbusters because I felt like they would provide a style and tonal shift the series needs to survive. Reitman fits that mold in a different way. If this movie works, Sony will absolutley turn things up to 11. They didn't build a mini Firehouse on their lot to not churn out Ghostbusters material. Cartoons, TV shows, more fan fests, who knows what they could do if this works.
I guess my point is while this Fan Fest thing seems like a bit of a debacle, I still have some faith we're in good hands.
Also, and this is the WILDEST speculation, the prospect of Rick Moranis coming back to acting excites me to no end. Doesn't even have to be Ghostbusters, but imagine how much people would love it if Sony announced he was coming back.