Now that it's sort of obvious that the New-Ruins are more or less a director's cut of the original time line, it seems clear now that the writing class story arc is taken on an importance it never had before. As howtheduck said, Elly will be shown to have genuine promise as a writer only to have her potential squashed by her 'loving' family. The casual, unthinking malice and selfishness on their part will change how we see them and how we see Elly herself. This is because, as I've said, Elly seems to have spent her life trying to become a person in her own right instead of someone's something and never quite got there; her one shot at becoming Elly the writer instead of John's wife or Mike's mom having been taken away from her will inspire her to seek revenge by controlling their lives. Since we know she succeeds, let's see what they did and how she nailed them:
John: It seems to me that the arc will end with John issuing an ultimatum that more or less forces Elly to give up her dream until such time as her children are old enough to take care of themselves; this will be seen as the insanely panicky over-reaction to a non-event that less rigid souls would not use as blackmail material. The means of her vengeance will be to encourage his model train hobby; since she knows she's a boorish perfectionist, his need to tinker will drive away lesser enthusiasts, isolate him and turn him into a walking punchline.
Mike: It's not hard to see who causes John to go loonie and browbeat Elly into flushing her hopes down the crapper. Something that Mike does will so horrify John that he goes looking for something out of the ordinary to blame his own failings on; that something will, of course, be Elly's attempt to better herself. To put it bluntly, Mike has to become a flabby shnook churning out pabulum for Lifetime because his idiocy ruined Elly's life.
Liz: It seems to me that the Settlepocalypse is simply Elly getting teal-and-lavender revenge on her daughter; if she can't have an exciting life, neither can Liz. This is why she went out of her way to sell a man she knows to be the same sort of whining moral bully and smirking hypocrite as John.
It could also be that Elly's later refusal to take child safety seriously as she should is a nasty side-effect of John's cancellation of her destiny; since running around like a fool keeping idiot children from killing themselves is getting in the way of her happiness, she'll do so with great reluctance.