I actually think it might be better on second viewing because then the audience will actually know what's going on with Ego's kind of seduction of Peter Quill and Yondu's race to save Peter.
On first viewing, the hints were there but Peter and Ego playing father and son felt aimless and, honestly, The Sovereign storyline felt disconnected. I felt like I was switching channels between two different stories.
And Mantis went from almost explaining Ego's evil plot to not doing so for half an act for no real reason. Gamora pretty much literally stumbled upon the answer that finally got Mantis to tell the story she was going to tell Drax.
Plot-wise, you could pretty much cut Nebula out altogether and not make a huge dent in the story.

Thematically, I also felt that it pulled some punches. I'd say the theme was The True Meaning of Family rather than The Love of Family.

Yondu is an interesting case because he's a guy who turned his back on family (Ravagers) by grabbing up Ego's kids, then when he found someone to call his son, he turned his back on his crew, always doing what was best for Quill than what was best for his crew. The film went the easy route by making Taserface a cruel, evil person but within the theme, he and the other Ravagers were 100% right to mutiny - Yondu didn't have their best intentions at heart.

Similarly, I thought the happy hug moment between Gamora and Nebula fell flat because Gamora was pretty much never really a sister to Nebula. Nebula was the wronged party, Gamora has her moment and apologizes... and then lets her sister fly off on a suicide mission vs. Thanos and Gamora goes back to her real family. To fit thematically, there needed to be a confession by Gamora that her family was the Guardians, not Nebula. She should have been sorry for not being the sister she was looking for, not acting like "Ok, NOW I'll be your sister." Again, it's a reason why I think they could have cut Nebula completely. Focus on Gamora struggling with her feeling that she's losing Quill to his father in a sense and have her seeking out the truth about Ego instead of running away from an attack by Nebula.

Again, I enjoyed the movie but I think it would have been better if they had exposed Ego's plot to the audience earlier and they didn't need to have so many layers of "FAMILY THEME!"