I didn't find myself exactly disappointed in the movie, but I can safely say it did not meet my expectations. The last Thor stand alone movie was rather dark and heavy, while this one is the exact opposite - colorful, light, and energetic. As much as I love a movie full of wit, sight gags, and hilarious moments, many of the ones in this movie felt...off. It pulled me out of what should have felt like a high stakes scenario - the fate of all Asgard was in the balance - and instead made it feel like it didn't much matter what would happen.
The entire portion of the movie spent on Sakaar felt like a waste of time. We knew Thor would escape, we knew he would return to Asgard in time for a final showdown with Hela, so at some point it felt like "Can we just get there already?" Also, side note, I usually hate long hair on men but I was devastated when they cut his hair off - made him look like just Chris Hemsworth, not the epic Thor.
I feel like an opportunity was missed to explore more of Hela's character and her relationship with Odin's past and Asgard's history. The sudden existence of an older sister for Thor felt, well, sudden, but it seems like there could have been a really interesting story there. It was touched on briefly, at a surface level, but I would have been fascinated to explore more of the dynamic between Odin and Hela. Why did he have such a change of heart? Why was she unable to change and instead banished? Why, exactly, did his death bring about her return? Had the movie delved into this story I think I would have enjoyed it more. Instead it made Hela into just another villain for Thor and company to easily defeat.
Overall I enjoyed the movie, but in a far different way than I expected. Had I gone into it expecting something campy and silly I think I would have enjoyed it even more. Mindset really makes a difference for me when watching a movie!