I think the reason why Black Adam is struggling to join the side of good (or turning over a new leaf) was because of his deceased wife Adrianna Tomaz, who has taught him to be more of a protector than a vengeful ruler.
That's what the comics are going to tell you but in reality it's just because Black Adam got redone in an era where Anti Heroes were the shit. It's a shame because he always made a great antagonist to Super- I mean Shazam. Who's gonna be his nemesis now :(
