Thoughts on the rating system

Last night I was thinking about the rating for Terminator Salvation and got really annoyed.  PG-13!  Are you kidding me?  The same thing happened to Live Free or Die Hard.  Some films just aren't supposed to be like that.  John McClane is meant to kick some R rated ass.... and the Terminator!  COME ON!  It's the ROBOT APOCALYPSE!  Don't you expect to see some serious shit go down?  Now I know they will most likely push the rating to its max, but still... it's kind of a tradition for films like these to have an R rating.  We grew up on that.  

Not to mention all the horror films in theatres these days with tame standards.  Also, remember when the new Predator vs. Aliens came out with a PG-13 rating?  Yeah?  I admit it wouldn't have made the biggest difference in terms of the quality of the film, but at least I would've gone into the theatre expecting a true Predator film.  

One more example from my childhood.  The Mortal Kombat film.  Where was Sub Zero tearing out a guys head and spinal cord?  Seriously!  The game had the balls to push the limits, it seemed like a crime that the film wouldn't do likewise.  

I know it is all about bringing in the most cash for a film, but I still feel some things were meant to be R rated... gives the kids a reason to sneak into the theatre.  

So what do you think?  Are my claims unwarranted?  Do you agree?  Can you remember a film that truly suffered from rating censorship?