We're going to keep saying it until everybody gets it: LEGO action games are pure fun because they bring LEGOs to life. That's it. The clever jokes that come out of whatever movie or comic book character is featured are an important part as well. The whole thing just makes for a unique LEGO style of gameplay that's not as juvenile as you'd think.
LEGO Batman 2 DC Super Heroes is a complicated ass way of getting all your favorite characters from "Super Friends" into a game without call it "Super Friends" (which somebody should do as soon as possible). Have a look at this trailer and set your inner LEGO mind free.