I really like the third act, it is a really epic and memorable part of the movie. But I don’t think it’s as good as people claim.

+Jessica’s arc was very interesting.
+Paul has shown himself as a powerful leader.
+Feyd-Rautha had an amazing intro and stole every other scene he was in.
+Gurney had a cool arc, like a second father figure to Paul (almost).
-Dune part 2 feels too much like an independent movie. Again it feels like they are introducing an idea over 2 acts (act 1-2) and then they wrap it up in act 3. 
-Paul and his mother being Harkonnen had not much of an impact on the story, if any. And it was executed poorly. I’ll give my 2 reasons: when Paul talks about the ‘reveal’ it had no relevance to the story. And when he storms into the emperor’s quarters and kills the baron (without even showing his identity to the baron) it still had no relevance. The baron was murdered by someone he didn’t even recognize.
- The final battle between Paul and Feyd-Rautha was very expected. The classic hero loses at first and then suddenly wins sequence. 
- The long-awaited emperor was disappointing honestly. He had so little screentime and was directly defeated, even though he had a massive army (sandworm power I guess).
-Where were these attacks with sandworms when Harkonnen ruled Arrakis??
-Why was Rabban such a weak character all of a sudden?? Even his final scene was a disappointment..
-Too much sand (lol).