It never actually explains in-game why the portal connection from the Ark to Earth jumped to Requiem as the Forward Unto Dawn was halfway through - I always assumed it was Mendicant Bias, deliberately only sending the 'Reclaimer' and no one else to Requiem, but I've never heard this discussed anywhere.

Also, in light of the new events in Halo 5, we now know it was Cortana who was destined to start the 'Reclamation' all along - so can we deduce that Mendicant Bias sent John and Cortana to Requiem in order for the Librarian to work her magic on them, and then used the Didact's ship to send Cortana to Genesis?

It would actually make the whole thing make a lot more sense - some overarching intelligence guiding John and Cortana toward the end goal of Halo 5, intervening where necessary and making sure they go to all the right places. Otherwise, there's a HELL of a lot of reliance on coincidence and random chance in the Librarian's 'plan'...

I also like the idea that Mendicant Bias has been guiding the Master Chief and looking out for him throughout the series, because it explains just how god damn lucky he seems to be all the time.