I saw this last Thursday. A lot of memories for me - for all the wrong reasons. I did a dreadful production of this in college! That said, we used every possible line and song (including, Country House) so somewhat familiar with the available material.
Watching the show brought back a lot of memories for me re: my younger days and it was very touching. However, the more I read some of your assessments the more I have to agree how this production felt short in several areas. Specifically, I miss seeing the contrast of the younger selves' JOY at doing these numbers when compared to tired, reflective older characters. This is why "One Last Kiss" was so well received in this production. I particularly liked the part where old Heidi looks back, acknowledges the ghost, and then the ghost sings, " . . . never look back". So haunting. I also appreciated that Bernadette was not afraid to be a little crazy/ugly in "Losing My Mind."
I was surprised they made Phyllis look like such an awful dancer, and that being the last meaningful sight of her in the show, where she had been so effective. I also did not think Ben's breakdown had the impact it needed; I could barely hear his lines over the chorus in "Live, Laugh, Love" and when he screams "PHYLIS!!!!" there were some chuckles in the audience.
If they do transfer to Broadway, I hope they invest in better use of the younger selves, bring back Victor/Vanessa and make the change to Loveland/breakdown back to reality more effective.
"Observe how bravely I conceal this dreadful dreadful shame I feel."