if a review were opinion, then why would certain people be paid to give their opinion on a movie so others could read it? that doesn't make any sense. that definitively means that one persons opinion on something is more valuable than anothers (i.e. you).Possibly a more accurate term would be criticism or critique?
I consider myself a critic, so when I review something that is subjective, I call it a critique, however a review is fully capable of being opinionated, and in fact it has to, it is extremely hard to hing an objective review on anything.
the only factors that are opinion have nothing to do with movie genre. if i were to review the notebook, which i hate, it would get a much better rating than what i think it deserves. an action lover would look at the review and think "yuck, this looks boring and stupid" based on the genre, with no help from the reviewer. that's what being a reviewer is, people don't give a damn about your opinion, they want the facts so they can draw their own conclusions.