In terms of the whole "Crisis" storyline...
Spoiler:
Is it seeming far too obvious? We know Arrow is ending after Crisis... we know Flash is not ending. Flash supposedly disappears in Crisis never to return and it's the only way to save the multiverse - but he obviously
doesn't. We've also seen loads of flash-forward sequences in Arrow, where Oliver Queen has been missing for a long time. So... Green Arrow takes Flash's place in doing whatever "needed to be done" to avert Crisis. Surely? They're making it easier to predict than ever though