I think this could work, introducing all or most of the actors/characters in a single movie. I doubt it would lead to the exact reverse of Marvel. Meaning EVERY single JLA member getting a solo film. Just the ones that ones are very popular.
Just look how much demand there is for a new solo Hulk film after The Avengers. But even than they are cautious based on the first two movies. So I could see skepticism on WB's part about a Green Lantern movie outside of the JLA. Regardless of who plays the part, Reynolds or someone else.
But if characters like Wonder Woman and the Flash are very popular it would work to give them their own movies.