I was confused about his obsession with Sasuke but I guess its more along the lines of him wanting to surpass Sasuke. He saw him as a rival...just a bit later it felt too much like he saw Sasuke as a friend...and there was not much evidence to prove that they were friends.
I feel like they jumped the gun with the CHuunin Exams because the arc with Zabuza had a lot more depth to it and then it just turned into your back to basics Shonen series.