Hamilton passed Alonso at turn two, Vettel passed Alonso into the hairpin, and I'm sure I saw someone (Rosberg maybe) make a pass into one of the chicanes. And there was the Perez / Massa / Rosberg incident into turn one. Perez got past Rosberg, who had cut the final chicane, then I think he passed Massa before reaching the hairpin.I went for 6, even though Hamilton won, the only thing exciting was Hamilton chasing down the leaders in the last 15 laps, that said, I can't remember a single overtake outside the DRS zone or in the pitlane.
Overall I'd give the race a 9, but I do agree with @Mephistoheles about the DRS making overtaking too easy.