Saw it for a 2nd time yesterday, and the rating remains the same (8.5). I was actually expecting my enjoyment to drop slightly, but the few parts I disliked weren't so bad the second time around (the Thor-Hulk tantrum scene didn't bother me as much, and the Warriors Three disposability was frustrating but expected). I only noticed a couple of important things I missed the first time around: Loki saying "Now you know how it feels to have been lied to" in the cell scene, since Thor has just learned about having a sister, which was a great progression in their relationship as siblings; Hela saying "Why Odin stopped at 9 realms I'll never know" which is...completely nonsensical -- it now appears to me a lot of her exposition about Asgard is just dishonest lies and half-truths to try and justify her own ambition and bloodlust, so Odin may be nowhere near as tyrannical in his early years as she suggests; I watched closely for it and this time I noticed that Miek (sp?) was introduced decently well before the final joke, since the first time I watched the movie I was admittedly completely baffled as to who the blob thing was under Korg's arm at the end.
I also observed the audience closely for what jokes worked and what didn't (it was a full theater just like my opening weekend screening). A lot of humour near the start didn't land, including Thor having to wait for the hammer (not my fave either), and there were only a few laughs for the dragon ichor and sliding head (which I personally found to be an extremely funny scene). I think the two biggest laughs were Hulk's sulking after being called the "stupidest Avenger", and the Banner faceplant into the bridge. People also laughed strongly at the ball bouncing back and hitting Thor in the head, and Loki's reaction to Hulk ragdolling Thor. There were quite a few laughs at the end when the entirety of Asgard exploded after Korg said that "the foundations were strong", which surprised me. However, no one laughed at Korg's line immediately afterward about "Oh, now there's nothing left", which makes me think this character reaction was a missed opportunity to use comedy to great dramatic effect. I wonder what might have happened if even Korg expressed sadness, and then the movie showed the same images of the faces of general Asgardians mourning. It could have added some real drama and weight to the ending I believe.
As I said in my initial review, Thor Ragnarok is a movie that is simply well made. It has areas where I think it could improve, yes, but overall it's just a well put together film. The story works, the third act works, the characters and their motivations work, and the visuals and music work. That is why it is so enjoyable and a real pleasure to watch.