Herolee, I totally understand what you're doing. Trust me, I get WAAAY more carried away than Herolee does on things like this and I was pretty pissed too at first - I didn't want to come away from the movie seeing Superman lose a fight to Batman rather than Superman LET Batman win to prove he's not a villain, or see Superman die and get some corny funeral scene.
But the more I think about it, the more I'm on board with it. So what if people call it cheap? So what if people think he's overpowered?
Superman will give his life to save a world that fears him because its the right thing to do. If thats the case, then Batman and Wonder Woman are the ones who aren't walking away with the most heroic scene, Clark is.
Superman and Batman weren't even founding members originally, maybe the league struggles to save the day until Clark returns to inspire and rally them as leader? We don't know yet. The possibilities are still endless.