No spoilers -
Guardians 3 was ok. Not great, not terrible, just bland and safe. The plot was ok, but the villains were extremely generic. Marvel has had this issue over the past couple few years. They don't know how to write compelling villains anymore. Now Marvel villains are just "guy in purple suit". The villain in this movie looked like he was wearing a repainted Vision costume. There was no artistic intent in the villain at all, not in the costume, and not in the character. The villain didn't have any real motive. He was just "bad guy #5".
The story centered on Rocket's origin story, but oddly enough, even with Rocket being the central character of this film, he was barely in it and literally spent the entire movie unconscious.
The runtime was about 45 minutes too long. The action scenes were repetitive and were just there to pad out the runtime. Action scenes are a good thing usually, but in this movie they went on for so long that I was getting bored and getting impatient waiting for the story to continue. Every time another action scene began, I started to roll my eyes because I knew it was going to take forever for the story to continue while the audience waited through the mind-numbing fight scenes.
I own the first to Guardians movies in my collection, but I won't be buying this one. It's the same reason I never bought any of the Transformers movies. Fine to see once, but I have no reason to want to see any of this movie again unless I were to fast-forward through all of the fight scenes upon re-watching it.