Originally Posted by
Zaresh
If you switch Dick for Tim, you don't have a Robin in the story. And you need a Robin in the story that came after Jason, not that came before, to reinforce two facts: that Jason had a succesor even when he was alive somewhere, still kidnapped by Joker; and a Robin that Bruce could use for his own guilt trip, seeing Jason in him sometimes, like an echo.
You can't do that with Dick as Nightwing, and you don't want Dick as Robin here either, because he's older than Jason by several years (already an adult), and also was already stablished as Robin previowsly, many years before the last game time.