About the other shards.

[Anonymoose]

I know they wanted the Scions to be established on the First, but I always wonder why they went for that particular excuse plot.

I think the big thing is that they needed what we saw in 3.4 to have taken place during the fall of the First, but also needed for enough time to have passed for the First to actually fall into a new status quo and not be mid-disaster. Almost everything we see on the First has a status quo that would take 100 years following the Flood of Light to establish. The wibbly wobbly timey wimey shenanigans helped establish more deeply-rooted fear and understanding of sin eaters, the entrenchment of the Light Wardens, the rise of Eulmoran culture, the raising of Crystarium, the politics of the fae realm, the conflicting sects of the religion of the Dark, the Warriors of Light becoming mythological villains rather than recently-living people who might be realistically understood, etc. Think about how much of the discussion with NPCs starts with, "Well, a hundred years ago..."

It was basically an excuse to make sure there was enough video game content and a new/interesting world setting.