I think it should be clear that Charizard fans are either actual children themselves, or generally more childish and impulsive, and might just buy the game outright because it has charizard. I don't think blastoise and venusaur fans are quite the same, and I think the value of discovering their dynamax forms, either as a community or on their own, will have a much greater impact than a dinky reveal trailer.
Charizard is the one getting shafted, unless the other two just don't get Giga forms.