I almost feel like Maggie/Mouse's sections were a pilot for the planned Maggie spinoff, which I wouldn't be against seeing more of! Maggie's POV does a great job making her a nuanced character and, even without her bad memories, her age lets her interact with things Harry can't. Which is a nice callback to the boogeyman story.
I think one of the most interesting things about ZD too is Jim's author's note about it, especially his acknowledgment Harry's life has to change with the fact he's a dad even if it means losing some of his audience. One of my concerns with Changes was if Maggie was just going to disappear from the series until dramatically convenient since it would've made her and Harry's relationship to her feel more like a cheap plot device. However, ZD's gone a long ways in helping assuage those concerns.
Plus, it actually gives me hope Harry might live a long while, considering how much of Maggie's fears are rooted in people dying or disappearing.