The other issue people seem to have had is one we have seen before in other next gen canons - beloved childhood characters being flawed adults and parents.

YES

I LOVE IT SO MUCH

See also: SO MANY OF MY OTHER FANDOMS

And no offence to Kylo Ren, for I love him dearly (from a safe distance), but, ummmmm, that's a terrible comparison.

I also find Albus having a crush on Delphi deeply hilarious in retrospect.

Oh wow, I didn't even spot that! I mean, the crush, obviously, but "Harry Potter's son has a crush on Voldemort's SECRET LOVE CHILD WITH BELLATRIX LESTRANGE*" no.

* Oh God, I've PRACTICALLY WRITTEN THIS FIC.