The Multiverse is NOT back, only Earth-2 and all of the former Earth-2 people are zapped to it at the end of the issue.
ALL of the former Earth-2 people? We know the heroes from Earth-2 found their histories altered at the end of the first Crisis so they now, supposedly, lived on the same world as the Earth-1 crowd all along...but who else, if anyone, made the move? Can we assume that average, non-costumed mortals from Earth-2 also found their way onto Earth-1? Or were they all killed except for the heroes? If some of them made it, which ones? The population of "DCU Earth" (or whatever it's been since '86) is not double that of Earth-1 or Earth-2, it's the same as one of those worlds. That is to say, we didn't go from two Earths with 4 billion humans each to one Earth with 8 billion. So billions of people must have died. Were they all on Earth-2 or was it an even ratio of Earth-1 victims and Earth-2 victims?
Logically, if a new Earth-2 is created in issue 4 of this new Crisis, did half the Earth's population, or 2 billion people, go to live on it? Or was a new Earth-2 created, complete with 4 billion new souls, and then the JSA was cherry-picked off DCU Earth and plopped down on the new Earth-2?
Sorry, you can tell I didn't read this issue. Are they saying Earth-2 was there all along, just hidden somewhere? Or did they create a new Earth-2?
Also, the JSA is, I gather, more than halfway made up of new members these days. And the new Dr Midnite, Mr Terrific, etc would logically be people born on DCU Earth. While it would make sense for Jay and Alan and Carter to go back to Earth-2, where they were born, why would the new members of the JSA be sent there when the only thing tying them to Earth-2 is the name they call themselves while in costume? I mean, I can say I'm the latest Hourman, but that doesn't mean I belong on Earth-2.