But then people would be mad when their favorite characters died. You can add to universe, but not destroy, without people getting mad. The best you can really do is having something like Batman Reborn, where you get rid of Batman for a spin-off series. Support a whole bunch of those, and you could get something like a New 52 reboot where they become completely canon, but you're gonna want to bring back Batman / Superman, because people keep asking for those characters.
It's what people complain about with Marvel, what with female Thor and young female Iron Man (which really doesn't suit the character. Heck, the few times it has worked are with Captain Marvel and Spider Man.
Then let people complain, as long as the story is strong they will live with it.
I HATE it when the Silver City, angles, demons, and Hell are brought up. Their depictions are just so far from what is consistent with the Judao-Christian and Islamic depictions to the point of absurdity. But the quality of the writing that Mr. Zoat brings, makes it just bearable (note, I blame DC in general for that mess. They haven't respected other cultures in years, not just Christians, but Buddhists and Hindu's are treated like mystics when the Buddhist philosophy is highly rational. I digress enough).
"Bringing back Batman / Superman, because people keep asking for those"
I have 2 responses.
1) Writers could be more creative. Superman could be an old man, mentoring the next generation but he's getting weaker, so he does what his father Jor-El did and create a Neural AI so that he can continue to guide them but, as all beings must, he dies. Maybe something happens and the AI gains true sentience, so he is now doing his own research to help, but so much needs done, so many people need help. He creates a Clone of his original body and transfers his mind and spirit. Techno-bable, Techno-bable, it works but he has to transfer himself back to the computer every couple of days. (gives him occasional presence but allows new characters to stand on their own feet.)
I came up with that in 10min, a team of better writers than me could flush out the whole thing.
2) We have fanfics, and we have the multi-verse. We should still keep the Animated separate from the comics (and tv/movies). Just the pacing alone would mean that they would never work well together. But we could work out alternate realities. Fanfics have always been a bit 'hit-or-miss' but if fans want them back that badly they can write their own Gosh Darn stories. Free-market storytelling.
I would also have a team keep an eye out for the better writers to hire....... So yeah, promote the fan base and hire the talented ones.