I think people forget that Iron Man was the success it was because it was good. It had great reviews and reached a cross audience of people who don't normally like super-hero movies. Salman Rushdie raved about how good it was (granted he also said he didn't like the ending when it turned into a super-hero movie) and normally "snooty" critiques liked it too. This success crossed over to the other Marvel movies.
Wonder Woman, if it is good, will do the same thing as Iron Man.