I think an incredibly comedic trailer with loads of jokes and ghosts would turn people off of this movie very quickly. Ignoring the manbabies upset by an all-female Ghostbusters team, many people thought the first GB 2016 trailer was terrible because it included all that shit. I heard a lot of the same complaints that I've seen so far on this thread of how it didn't look nor feel like Ghostbusters. Trying something new keeps the franchise fresh, and going for a more mysterious tone with hints of nostalgia seems like the way to go about doing just that.