Comparatively speaking which other big AAA launches has been this smooth,
it's an achievement. In recent memory like already mentioned Destiny is the only one that had the same kind of launch with dedicated servers. Having access to the Azure cloud platform definitely helped with spinning up dedicated servers when needed, wish more games would use the cloud that way be it AWS, Google compute engine or Azure.
A p2p launch is easier the publisher only has to have capacity for matchmaking, if i'm not mistaken. Then one of the players console will act as the ground truth for everyone.