Well, in fairness, Angel, none of it was shot on film. All of Episodes 2 and 3 were shot digitally, which is stored on tape (most people don't believe that) not on a disk. So there isn't actually any film grain in either of those movies. But I know what you mean about the CGI being too clean.
In the earlier days of CGI, long before HD, CG scenes were deliberately "dirtied up" to make it blend with the film better. But with HD now they rarely do it.