If I was placed in charge of DC and Marvel Comics, these are the changes I would implement throughout both companies.
REBOOT THE ENTIRE LINE OF COMICS
All storylines currently in progress would be wrapped up, the worst-selling/extraneous titles would be cancelled, and the best-selling figurehead titles would receive complete and total reboots, starting over with brand new issue #1s. The slate would be wiped completely clean; there would be absolutely no "have my cake and eat it too"-styled reboots ala Crisis on Infinite Earths or Nu52.
THE CHARACTERS WOULD AGE AND EVOLVE IN REAL TIME
No more compressing decades worth of storylines, sliding the timeline, or utilizing cosmic resets to preserve the status quo and keep the characters static while the world(s) around them changes. One year of storylines in the real world would approximate one year of events in-universe -- no exceptions. As the readers age, start careers, get married, have children, and eventually die, so to will the characters in the books (The mortal ones with average human lifespans, anyway.).
LIMIT THE NUMBER OF TITLES FOR ANY SPECIFIC SUPERHERO
So that means Batman, Superman, Spider-Man, the X-Men, etc. only get one or two titles each; no more three-five-seven-nine+ titles for anyone.
NO MORE SHARED UNIVERSE(S)
Basically, each superhero would exist in his/her title as if s/he was the only superhero in existence; allusions to other superheroes in other titles would be done in only the vaguest of ways, and guest appearances/crossovers would be rare and more-or-less considered out of continuity.
ALL MAIN TITLES WOULD BE WRITTEN FOR AN ALL-AGES AUDIENCE
Brutal violence, gore, sex, and profanity would no longer be allowed. All primary superhero titles would be written so as to appeal to adults and children both. All the R-and-X-rated stuff is to be reserved for miniseries published outside of the main titles.
NO MORE "WRITING FOR THE TRADE"
Character and story arcs can go on indefinately, but specific storylines must be resolved within one-to-four issues; no more decompression.
CROSSOVER EVENTS WOULD BE RARE
There would be no more of this annual "events that shake the world/galaxy/universe/multiverse" crap. Events would be very rare events --one every seven-to-ten years or so. Furthermore, events would be written so as to be standalone miniseries; there would be no tie-in miniseries/storylines or interference with the main titles.
IF A MAJOR/SUPPORTING CHARACTER IS TO DIE, IT MUST BE WITH DIGNITY
Deaths likes this one
are all well and good when used sparingly, but deaths like this one
are completely unacceptable and absolutely anathema.
NO OVERPOWERING CHARACTERS
Characters must have limitations so that they can be reasonably challenged. In other words, Superman can't move planets or travel at/past the speed of light, Wolverine can't regenerate from atomic explosions, Batman can't beat everyone with enough prep time, etc.
