I especially like the comparison between the part where Bale-Wayne hangs on the ledge holding Ra's al Ghul, and he screams and it's extremely painful and exhausting, and where Robin catches Batgirl, and he's just casual, spouting a one-liner with no effort. That's the big difference, the difference between "realism" and camp what makes you either care or facepalm.
It's not really about dark or light, serious or comedic. It's more about what to do that an audience can relate with these characters and the film. If everything is camp, then there's nothing at stake. If the characters are unnatural, you don't care. And I think making a scene comical where, for example, a life is at stake is where people stop caring.