I'm gonna go out on a limb here and say they probably just won't bother to explain the stuff they retcon. They never really tied to explain any of the original game mechanics through the story until it came time to introduce new subclasses. Like: [i]"Hey y'all can obviously time travel at will to relive these missions whenever you want but we're never ever going to discuss that even though time travel is a central feature of the plot in several areas."[/i] If they're as focused on 'simplifying' as they seem to be, then they're unlikely to get fancy about narrative justifications for anything. They mostly just do stuff.