I don't literally see Looper when I see Deadpool 2 either but it was recently pointed out to me and it's true that if you look at the bare bones of it they are both stories about men who attempt to kill a child in the past to prevent his ascent to super villain status.
The main difference is that in Looper the man in the past who tries to stop the assassination is the assassin himself as a younger man.
I just mean that films can have a lot in common but I didn't see a great deal of similarity in the way Superman and Wonder Woman were presented. Just basic similarities that most superheroes share.