Elseworlds Finest w/Supergirl & Batgirl
I chose "Other"--and picking an actual Elseworld (not what I would want to be an Elseworld)--my choice would be Superman & Batman: Generations. John Byrne showed how you can do a real time series, using all the different eras of DC history, weaving together different concepts, and respecting the work of various creators. The third series wasn't the best, but the concept was open to lots of possibilities for new stories.
I can name several Elseworlds stories which I'd love to see get a few "well-written sequels" -- maybe even a regular title set in that unique little timeline and lasting for ten years if anyone besides me would but it! -- but none of my favorite Elseworlds would be a good fit as "this is the new foundation for dozens of monthly titles which will feature the new 'mainstream version' of all DC's characters for the next decade or more!"
That includes the items specifically listed in this poll.
Count me in on the "Young Justice" take
All cruel people describe themselves as paragons of frankness.-Tennessee Williams
The thing is books like New Frontier and Miller's Dark Knight didn't get an Elseworlds label. Since this poll uses the "Elseworlds" designation, I figure those are the only candidates we're supposed to consider. Otherwise, I could just as easily say that I want everything back to the way it was before CoIE--but they never did an Elseworlds book that offered that possibility (althought there were a few that came close).
And then see a new larger DCU expand from there.
Batgirl, Justice League Beyond 2.0, Letter 44, She-Hulk, Swamp Thing
Amazing Spider-Man, Inhuman, Ultimate FF