I thought it rambled and was a little long, but I didn't think it was flat. I think he wanted to contrast with Slow Joe's speech, which was little more than a blurb. I cannot imagine Joe staying on script as long as Trump did last night.
BTW on a side note, I thought Karen Pence wore an expression of disgust throughout the speech. She looked like a soccer mom who finds Trump's tweets offensive.
The nation came to hear what was on Trump’s mind and so did everyone in that audience. He have them a show they will never forget. The opera was icing on the cake.