I think Jim's point was that it wasn't necessary to do COIE to progress the universe, because it just tangled everything in nots. Stuff like All-Star is an example of what the DCU could look like if it wasn't concerned with constantly rebooting and rebuilding continuity. Stuff was changing pre-COIE and there is no reason it couldn't have continued to grow organically from there.
It's way too late to reverse now, but it was never necessary to begin with.