There is an argument to be made that if a PV is intentionally misleading people then that isn't justified necessarily since a PV is supposed to clue in its audience on what the actual content is.
However, I thought the PV was actually very accurate about its content and I'm confused how so many people got confused by the preview anyways. When I first watched it I got the distinct impression that the characters were engaging in crazy delusional fantasies, and that is without having read the synopsis. Just look how theatrical the characters are at some points where they're doing poses and the like. It's either a fantasy or the cheesiest action show ever
. Furthermore there's a distinct comedic feel to it throughout the PV.
Anyways the only people in the West who are going to be watching these previews are people who are going out of their way to see what's coming out in Japan ahead of time. Seeing as we also have a synopsis, which isn't hard to find at all, there shouldn't be an excuse of "time" used here. Most otaku in general in Japan do their research as well. The casuals? I doubt they're going to even be seeing the previews and at best might just filter in when the show finally airs.