A companion piece to the “Earth-1985 — what would you like to see?” thread.
As of Doomsday Clock #12, a new explanation for Earth 2 had emerged: it was the preservation of the Golden Age that came into being when Barry Allen became the Flash, the Speed Force came into existence, and the Multiverse was born. There's some question about its history after the Crisis; one school of thought is that it somehow survived as a distinct Earth but was moved away from where it used to be and was thus inaccessible from the post-Crisis Earth; the other possibility is that it was destroyed in the Crisis and its last remnants were merged with Earth 1 to form the post-Crisis DCU. With the DDC#12 notion that worlds split to preserve all eras of Superman, it's possible that both happened.
It's also possible that if a copy was created as a result of the Crisis (or by the retroactive alteration of the Crisis at the end of Convergence), that this copy somehow got dragged into the Infinite Crisis and helped provide the “DNA” for New Earth and its Multiverse. It's possible that Bart Allen was sent to this Earth during Infinite Crisis (before Alex Luthor summoned the Infinite Earths) and that there Earth 2 Lois, Wonder Woman, and Superman all find their way back there upon their “deaths” (there were some retcons in the TPB of Infinite Crisis implying something to this effect). It's also possible that it was “pulled into” the new Multiverse and became the new Multiverse's Earth 2 (which, as revealed by the final JSA Annual before Flashpoint, was effectively a continuation of the pre-Crisis Earth 2). Then Flashpoint hit and rewrote the Multiverse. But it's arguable that if the aforementioned “preservation split” feature extends beyond the primary Earth, a copy of the JSI Earth may exist somewhere out there, distinct from the New 52 Earth 2. And it's also possible that as of DDC#12, the Rebirth Earth 2 last seen in Earth 2 Society has been reverted to something resembling the original Earth 2.
All of which is a long-winded way of saying that at the moment, Earth 2 can potentially be whatever DC wants it to be; it can even be several of those things at once, in the form of multiple iterations of Earth 2. With that in mind, what would you like to see?
I'll post my own preferences later; I'm currently at work.