To be honest I think video game ratings are pointless.
The list of the type of things is fine, and parents should not depend on a letter to dictate to them the appropriateness of a game.
When I have kids, I'll encourage them to partake in what I found enjoyable as a youth, and hopefully get them to play some of the old classics and not the mediocre "it prints money" shit that has been flooding my local game store for the past half decade. But thats beside the point.
I think that parents should take a more active role in what their children do for fun and if the media would pull their heads out of their arces and take an informed stand on whats going on there would be less need for ratings. If Jimmy the impressionable 7 year old farts for brains wants to get Bloody Manslaughter: Return of the Hatchet Killer thats fine by me, chances are he'll just have a few nightmares and that'll be his lesson learned. And if his idiot parents didn't check the content of the game thats their own stupid fault.
If more parents took the same approach to raising their kids as mine raised me, as in letting me do whatever the fuck I wanted as long as I didn't permanently injure myself or hurt/harm anyone else or other peoples stuff, the world would be a generally better place.
I grew up playing most of the violent games during my child hood, I was playing Duke Nukem when I was 5 and I was adicted to Quake at 10, and I'm quite a caring and passionate person who hates to see people hurt or get hurt.
So long story short, I think the ratings are doing bugger all to stop stupid people being stupid. If someone was born an idiot they'll probably end up being an idiot. Appropriateness depends on the person and how they perceive things. The original Terminator movie used to be rated X... and now its PG-13 or whatever. And if everyone thinks that Timmy the "I take everything literally" 7 year old Gropecunt stabbed his schoolmate because he played Gears of War and not because the kid he stabbed was a dick and deserved it, thats fine by me.
So don't let Timmy play those games, doesn't mean that I can't play Blood, Tits and Gore 2: The Revenge of Bloody Knives.