Look at Batman now its had numerous spin-offs, tie-ins and titles. At one point as many as ten or more per month! All could be folded into one Batman book or two Batman, which could feature all spin-off titles like Catwoman, Batgirl, Gotham Nights, Birds of Prey, Robin and so on and Detective Comics which would feature a shorter Batman lead and detective-related features.
But, but DC tried a weekly book, Action Comics Weekly, and it was a dud and Marvel tried a bi-weekly book, Marvel Comics Presents, and it ground to a halt after a while why would this succeed if those floundered?
Because if publishers replaced their entire lines, readers would have no other options. The reasons Action Comics Weekly and Marvel Comics Presents eventually floundered were many, first they featured a lot of second-stringers and (in some cases) weak art, their stories were often inconsequential adventures and the cover prices of these titles were higher than the monthly books. If a reader can get a full issue of Wolverine for less money than a more expensive book with an eight-page Wolverine story plus solo stories of Shamrock, the Arabian Knight and Willie Lumpkin, theyre going to pick Wolverine! These books were doomed from the start and they quickly deteriorated and fell apart as creative teams went elsewhere are weak filler was shoveled at the reader.
If I were DC Id do one cartoon book, taking the place of all animated titles Scooby Doo, Bugs Bunny and all the rest. Then Id do Batman, Detective Comics, Superman, Action Comics, Wonder Woman, Justice League, Flash and Green Lantern all other books could be broken up and serialized in those titles. The lines in many cases are obvious, in others not so much. Blue Beetle, Booster Gold and Teen Titans could fold into the JLA book anything god or mythology related like Captain Marvel, the Demon or the Spectre could fold into Wonder Woman and so forth. There could either be a couple Vertigo books or have them be the exception and keep their current format if there arent features strong enough to carry a book.
At Marvel Id do Amazing Spider-Man, Fantastic Four, Incredible Hulk, X-Men, Avengers, Captain America, Thor, Wolverine, Iron Man and Daredevil. X-titles like X-Factor or Deadpool would fold into X-Men or Wolverine. Plus books that often struggled could be given a few pages not hopeless losers like Captain Ultra, Aunt May or Squirrel Girl but Namor, the Silver Surfer, the Inhumans, Dr. Strange and Nick Fury!
In both cases I chose historically important, long-running titles with faithful fan followings. In some cases, bi-weekly or even monthly titles might be better solutions. I know DC is contractually obligated to publish Wonder Woman monthly but maybe she cant realistically headline a weekly book so maybe she has a monthly book backed with great features. Maybe Marvel would do better alternating Daredevil and Iron Man every other week but the idea, I think, has real merit.
Both companies could produce the same number of pages that they are now but instead of having a monthly She-Hulk book, for example, which keeps getting axed and restarted her adventures could run in five-page, weekly installments running in the back of the Incredible Hulk.