I've been going over the plot of Chrono Cross lately, and it seems to me that in the ideal timeline, the need for the Promethius Circuit to exist would be gone.
Without the Promethius Circuit, Robo would presumably be free, and without FATE wanting to disengage the Promethius Circuit, Lynx would never presumably travel to Lucca's house and kill her.
Do either of these assumptions make any sense?