The biggest thing that would be required would be a bunch of people with white hair who are willing to commit body-and-soul to such a move.
Many of those of us with white (or missing) hair are already up to our necks (or worse) in administration. When I'm asked to do something new, I always ask back "What do you want me to stop doing?" But the current ACL leadership is already spending a lot of time managing publication in conferences and one journal. Except that this effort is mostly wasted in obsolete publication methods instead of leading the move to open access and fast turn-around, quality reviewing. When I had some executive power at ACL, many years ago, before there was a web, I was one of the movers with Stuart Shieber in getting rid a the restrictive copyright assignment for conference and journal publications. What is are current ACL executives doing?