I have to side partly with
@DCDAVE.
Much of general audience doesn't care at all about things like DCU, DCEU, etc. Right now they've seen a Flash movie they didn't like and it's one more "DC" project that falls into that category.
About those interested in labels and behind the scenes stuff, I still read a lot of these people mistaking
The Flash for the first film in the "Gunnverse", seeing it as a passage between the past and the future, which in reality is not the case.
My point is that, as I said in another thread, from a marketing point of view, DC/WB probably made a mistake communicating about the reboot in detail so early. Sure, things can be made clearer later, but right now everything is way too intertwined and it just muddies the waters for nothing.
Here again, there are still two films from the old regime to be released. Yet, they didn't wait to already announce Muschietti as the future of Batman. Even if he may deliver something different in 2 or 3 years, already teasing a cinematic rebirth with the guy who currently has a poorly-received film in theaters, with in it several versions of the same character he'll adapt again later, is very questionable timing...
Anyway, as others have also said, it will be 100% on
Superman: Legacy to bring back general audience interest. And, in my opinion, that can only be achieved by showing a true change, perceptible from the very first images, teaser, whatever. Beyond the necessity of having a solid story, that thing must not look like any other superhero movie and I think Gunn knows this. I guess his desire to develop
"an aesthetic that has never existed before" for the film might,
partly, also be motivated by this.