@batmannflash: I think Wonder Woman, Green Lantern, and Flash would become the new Trinity. With Aquaman, Martian Manhunter, Green Arrow, and Captain Marvel becoming more popular. The only reason I left Nightwing out is because if they don't have Batman then they probably won't have Robin.
The big two of DC's respective Mythos' make up like half to two thirds of DC and their Mythos' touch like everyone else's in DC. Without the World's finest and their mythos DC would be a much smaller company, I mean like downscaling to IDW and Image size.
If they lost them now? never mind, the mainstream will never affiliate them with anything else anyway.
I say it's feasible they won't be hurting that much, rather they'd be able to concentrate on other characters and highlight them, flash point pretty much based off of the flash and i found it awesome. Green Lantern, Wonder Woman, Martian Manhunter and co. are still there too.
Think about the justice league titles without the two.
If they loose Batman they'd be down like 40%, if they lose Superman they'd 20% but the GL, Aquaman, Flash, WW titles will be enough to keep them above the rest of the publishers except Marvel and if the said publishers don't get hold of any of the characters. People who say they'd be below Valiant or IDW etc don't know much about the market shares.