Here's what we know about the Uchiha clan:
- They have the Sharingan
- The ancestor was a son of Rikudou
- They wanted to attempt a coup d'etat to take over Konoha
- Power-hungry
- Fire affinity in the clan
Now the Hyuuga we really don't know that much about. Byakugan, Branch family, main family, curse seal, etc, etc. We have no background on them or where they came from.
And the thing about Naruto? He's the main character, character development takes some time, you can't expect Kishi to go: OMG HERE, HAVE ALL THE DETAILS ON NARUTO. Who's gonna read it? It's called PLOT.
What would you like to know about Sakura? Her family is probably not that important, so Kishi never really fleshed out her background, but will develop her character itself later on. Whoop-dee-doo, Sasuke gets some more screen time, but overall, Naruto still has more scenes. Because why? PLOT. A story is always divided into different points of view. Pick up a novel sometime. Some chapters will have one character taking up the whole story, while another will have a 2nd character taking up some parts.