I've watched the trailer twice, and I think I like it. Not sold yet. The way Billy in his Cap form acted seemed a bit silly, like that bloke in the Night at the Museum films, or the way the hero acts in Pixels. Yes, I know Billy's just a kid. I wonder if it's too slapstick.
As I have seen very few modern superhero films, and I haven't particularly enjoyed them, despite bits of them being quite entertaining, perhaps I'm not the best person to comment. By the way, I am really ignorant of many modern actors, so I'll have to look up Mark Strong. Haven't a scooby who he is.
Last night, we watched a 1950, b&w British thriller, titled "High Treason":-
https://www.imdb.com/title/tt0043637/and found it much more entertaining and atmospheric than most modern American, overlong, emotions hanging out films that we see.
But, as a big, Big Red Cheese fan, I will watch Shazam. At the Stirling Con on Sat. we were speculating on what villains would appear, will Freddy get to shout "Captain Marvel"? (He can't, really), how in heaven's name can they fit Mr. Mind in, will they deal with Billy shouting "Shazam" and nobody seeming to realise that wee boy is suddenly a big, big superhero? Made for some great patter and boffo laughs all round.