I think The Illustrated Mum is one of her best books - it has aged well, for being written in 1999. But I worry it's going to have the pitfalls of Think Again that made that book a disappointment for me.
I found Ellie (and all characters really), in Think Again, to simply be an adult version of her as a child - there was no real growing, no development, and it was the same old problems as in the original Girls books. I get that the character needs to be recognisable, but we also need a reason for there to be another story - something needs to be new. I can see it already: Dolphin has her head in the clouds and is ditsy and can't decide what to do (and loves drawing so she became a tattoo artist), Star is the sensible, serious, got-her-life-together one, and Marigold is Marigold. I hope that something has changed in their dynamic for this to be worthy of a continued story.
I also think Jacqueline has a major issue with writing men - the only moral and 'good' men in her stories are gay. That's difficult enough to dance around with her children's books, but her adult ones which are largely about relationships - it just doesn't work. There isn't enough nuance. With the description of Picture Imperfect seeming to focus on Dolphin's multiple dating options I worry it's going to be a predictable drear-fest. Both men will let her down and she'll move in with Star because family is always best and men suck.
Jacqueline, to me, always struggled a bit with Marigold anyway - The Illustrated Mum ends very abruptly. I hope that 26 years later, and in the adult genre, she feels confident addressing the gritty, difficult issues. I hope we really see Marigold's manipulation (she read as a narcissist to me in a lot of ways, as well as bipolar) - I think it would be interesting if Star was entirely no-contact with Marigold but not with Dolphin. And I do hope it addresses the state of mental health services in the UK and the burden it has on families.
I'm just not confident, sadly.