I'm wondering how much of my feelings toward this are because it's a play and only the script was released to the public. I'm curious about how I would feel walking out of the play instead of finishing up reading the script.
But, the script is the only thing available to me at the moment so that's how I took this story in. For me, it relies too heavily on the "cool things" from all the past Harry Potter books and not enough on it's own original creations. They have a whole magical world to explore and instead they revert to the things we already know.
It's like being constantly nudged and winked at while saying "Remember this thing? Hey! How about this thing? Remember how much you liked this?"
I'm hoping the writer just needed to get this out of their system to tie the original generation together with this new generation of characters. Maybe the next story in this universe will be more original. I really hope so.
All that being said, it's not a bad story. It's just not great. I'm glad I read it once so that I know the story but I don't see myself revisiting this one again in written form. Maybe someday the play will come near me and I'll give it a shot.