It worries me that it looks like the League will have no memory of ever knowing the JSA. I hope they don't erase all pre-FP JSA appearances. Losing Johns' JSA and Robinson's Starmann would be sad.
DC just doesn't seem to like the JSA. Apparently Didio's original plan for Infinite Crisis had them a few of them dying in it as well. And giving the book to Willingham and Guggenheim after Johns has to be some of the worst decisions made especially when there were better candidates to succeed him.
Judging by how they tell the stories of bringing back old characters or continuity in Rebirth, from Wally to Superman to Kon-El, that's how the story's going to start. No one will remember a thing. Then there will be some drama and conflict, but after the big climax... or the aftermath... the memory will return... or some version of it. A combination of what fans familiar from the past but modernized to fit with the current vision.
Unfortunately, I can't argue that .
I think right now the viability of any DC property depends on whether the architects care to use them, so the Legion have Bendis and the JSA now have Snyder.
It's unfortunate that Wally couldn't get the same kind of momentum but I think DC Editorial is super-strong when it comes to The Flashes otherwise Snyder would be writing Wally in Justice League.