Here's the thing.
I agree with Cynthia that Shazam works best as a kid's story. I don't think it works as an edgy or adult book and I think the sales tend to prove that.
However, at the same time, people who demand new children's stories for themselves to read when they are obviously well above the age of majority are just as bad as (if not worse than) the ones who demand we turn children's characters into adult fare.
For example, I liked Dr Suess books as a kid and I wouldn't want to see a bunch of shitty "grim and gritty" sequels written for thirty year olds.
But at the same time I don't lay awake wondering why no one is cranking out "the Grinch Saves Easter" or "Three Fish Four Fish Yellow Fish More Fish" for MY reading pleasure.
