As mentioned, she guides Barry Allen at the end of Flashpoint to "fix" the timeline...and this is what we got instead.
If I had to guess, given the Superman "Retroactive" issue ('70s? None of them were particularly memorable), it could be Harbinger, the Monitor's flunky who gets dragged back every so often to no useful effect.
Having compiled the History of the DC Universe (available now from retailers...if you live in 1987), it would make the same sort of sense (don't ask me WHAT sort, please) as bringing Superboy-Prime in as a major character for Infinite Crisis.