Well, aside from the fact that the Flash and Aquaman films will already have wrapped or almost wrapped production by then, and that their performance will be heavily contingent on how those characters are received in Justice League.
If JL gets a similar reception to BvS, I really think WB could be looking at multiple outright bombs on their DCCU slate.
That said, I wouldn't be surprised to see a *lot* of schedule rejiggering over the next few months, so we might get a 2018 slate that doesn't reflect such unwarranted confidence in Justice League - Batman and Suicide Squad 2, perhaps.