Valid point.
The elaborate contingency plans seem pretty unnecessary--not just for Diana but the others--when we routinely see them wiped out by the most mundane of things. Considering any given issue of Justice League will have half the team flattened by a villain's sneeze and the other half tripping over themselves, I think Bruce might be overthinking things.
Batman: "If the League went rogue, who could possibly stop them? What could anyone do?"
(two issues earlier, Deathstroke single-handedly wipes the floor with the entire team)
Batman: "Certainly, the LEAGUE is the greatest threat to this planet! Someone MUST keep them under watch!"
(next issue, the Riddler hypnotizes the League into a coma and runs off with their cash)
Batman: "My plans are a necessary evil. I specially tailored each one to exploit their weaknesses, because that's the only defense we have against them."
(three issues later, a stray cat leaves the entire League in traction)