I echo much of what has been written here.
1) There's no way the committee calls this a revival. That's clearly a plan to get out of HAMILTON's way. The book is entirely new, the score is completely rearranged to tell an entirely different story, namely the backstage creation of the musical and the effects of its success.
2) I agree the first act is thrilling. Wolfe's book, his swift direction, along with Glover's hair-raising tap numbers are sublime. The act ends on an exhilarating high.
And then, Act Two. Specifically, the middle of Act 2. Showing the show's success keeps the story from Act 1 continuing. But once it starts to attempt to show how the show has affected the lives of the creators, it loses focuses quickly. It's not shocking, in a way; many biographical films and plays lose focus as they try to cram too much of a person's life into the piece. And life is meandering, repetitive, and this makes for unfocused storytelling. You can see the unfortunate events of their life from amile away. And worse, each star's 11 o'clock number feels rote. I thought, "Oh look, Stokes does a 'Live, Laugh, Love"" and "Oh look, Audra does..." You get the idea.
In the end of Act 1, we know we're working towards Opening Night. What are we working towards in Act 2 - death? Sadly, yes. And no, that's not a spoiler alert. They all die eventually - like we all do - and anyone could have told you that. So, to spend an entire closing number telling you what became of EVERY SINGLE PERSON in the show, all the way to death, is mind-numbingly dull and seems so far from Act 1's juggernaut of energy. The end of the show should tell us what it's all been about, not peter out until we know how everyone died.
Sadly, the most telling moment was the dialogue before the Finale. Someone asks Audra's character if it's time for a song, and she replies something to the effect of, "Of course. But we'll do it with a lot of energy, because that's what we do." If that's not a perfect example of a book that doesn't even know why the FInale song is about to start, I can't think of a better one.