Non-spoilery, unpopular opinion: I am (only three scenes in) enjoying reading the play. I am reading aloud to Shog, so it will take some time to get through the play; Shog has limited patience and interest in it as he's an Epilogue? what Epilogue? man.
I'm not going to lie: I teared up when the Potters went through the wall as a family.
I like that James gives his brother shit; brothers do that.
Lily's excitement is palpable, and I love that Uncle Ron is her favorite—and that he seems so happy and well-adjusted.
The parallels between Harry's meeting with Ron on the train and Scorpius's meeting with Albus are good. I like the bonding over "candy," and Albus' refusal to be told whom to befriend.
A + S = preslash! For me, their love is "canonical" as of that glance of understanding they share about father-son issues. (Well, okay, it's clear that they're meant to be friends from this point on. *g*)
And now, a word about Rose: Rose is an average kid dealing with being the child of famous parents in a way that seems perfectly normal to me. She's no doubt under enormous pressure, even if it is only in her mind (or coming from people outside her family, but I'm sure Hermione expects great things from her). She's decided to roll with her fame rather than hide, which I can see will be problematic, but I feel like she'll grow out of it. She didn't have to say the thing about Scorpius having a nose. That was sweet. She's not mean, just very concerned about standing out in a way that most kids are at this age. Mommy issues do not help this.
I know, I'm only three scenes in and responding to a lot of things other than the text, but I am eager to read more. I did not think that I would be!