Okay, then, who becomes the new Darkseid? Who is THAT badass?
Nobody, Pro. That's the fatal flaw. You can't kill Darkseid. There's no one to replace him or who poses that serious a threat to Superman. That's why this thing is doomed to fail, no matter how fun it is to watch.
Darkseid is overplayed and overrated!
Killing him off would be the greatest move DC has done in years!
There are plenty of ways of replacing him, the main one being to upgrade someone powerwise like they did when Hal became Parallax.
