How can I rate something that is not over? We still have one day of epic racing ahead! Might change my whole opinion of the race... (I'd like to see the last-day short-to-mid length ITT return in either the Giro or the Vuelta; a breathtaking ~30 Km fight for the podium, now that's a ceremony worthy of closing a GT.)
I think I would rate this Vuelta with a 7.5, but I don't know if I want to follow the convention to round that up. Froome's attacks, despite lacking the form to distance Quintana, were refreshing; he basically won the tour without ever showing such attacking spirit, save for a loony descent. Chaves' courage to attack from afar and snatch the podium from Contador is also something I would like to see more often. The break action has been good, too, so I'll cherish that memory as well.
However, despite a promising field, the Vuelta was also severely lacking in some points and lot of that had to do with the route. The level of sprinting was sub-par for a GT, as is more often the case in the Vuelta. To truly be a "Grand Tour of Cycling" instead of a "Climber's Fest", a GT should offer a variety of terrains incenting a varied field of top riders to come and compete. However, we seem to be stuck with the ridiculous notion that the only proper action in a GT is climbing action.