This is my own opinion,so don't get mad about it.
I will start this thread saying the obvious, Superman and Batman are obselete superheroes and both are not interesting.
Sure, the man of steel and the Sherlock Holmes bat-disguise guy where popular in their times, but now the are totally the opposite.
Let's start with Superman:
This guy was amazing in his first years, but now is the second most gary-stuish superhero in the history (the first one is Batman), why? His plots are stupid and are always the same thing. The bad guy comes, destroys the city (or the world) killing millions of people, the big bad guy beats Superman and let him live, the next part of the comic is Superman beating the bad guy from nowhere with a mystical unknown super-duper power.
It's pretty obvious the reason why Superman became so strong compared to his first version was because comics were (and are) losing customers and mange heroes as Goku and Seiya where more interesting than the big muscle man with perfect moral and this is something I want to talk.
Superman is perfect, and he is the pinaccle of morality no matter what, he will always let the villain live knowing he will come back and will do the same because... well... HE IS THE FREAKING VILLAIN.This is boring coming from a superhero. Most superheroes have no mercy and they just kill the villain because they know the guy will never be a good person. The only reason Superman is so popular compared to better superheroes is because he is the first concept of a superheore, but as a concept, he needs to die and be replace.
He is definitely the worst superheore actually. Why? He is a street fighter-just peak human, no more. His fanboys made him invincible with something they call 'prepare time'. Batman was cool when he used to fight the bad guys like Joker, Bane and more street fighter level characters, but now he's a god-like not god-like superheroe. His 'prepare time' is just an omnipotent tool which will always give him the win in fights. Superman became mad? Kryptonite gaunlets. Darkseid became mad again? Radion bullets ftw.
I mean, why is justice league important if Superman and Batman can do everything WW, MM, Flash and the other guys can do and better?
What do you thing? This is just a personal opinion, just that, and my opinion is Batman and Superman need to die forever as the good heroes they were once.