Terminator: Salvation

I was reading up on this a little bit ago, and the dudes who made it were saying the rating wasn't decided until the flick was done, and it just happened to be PG13. I'm not sure if they're just saying that so they don't look like assholes, but I don't think it's that big of a deal.
I'm a pretty big fan of the first two films, but couldn't stand the third one. It was like.. the message of the first two was you can change the future or whatever, and then the third one was all like, "Well... you can't actually do that. Sorrrrry." Kind of retarded. Anyways.. I'm sure most people agree that the third one blew, whatever. I'm interested in this mostly because, ever since I saw the scene where those treads are running over a bunch of human skulls, I've always wanted to see an entire flick set in that time period. That's what the third movie should've been. A prequel. So hopefully they don't screw this flip up as bad as the third movie did.