I don't, really. I expect some clarifications, and potential new, not-contradictory information where applicable (and there's plenty of room with what has been established for additions of these types), but not outright changes to things already established. Superman's continuity is changed a lot, more than most properties, but even then they manage to wait some years before changing it. By the time Doomsday Clock is over, Superman Reborn will only be slightly over a year old. That would be a new record for them changing things for the character. Its narrative nonsense to establish things and not even let it mature and gain any root at all before changing it all over again, and for all their faults I still trust they won't jump the gun that soon. Even the New 52 got five years.