Death is a tool I utilize a LOT in RP. Thing is for me, it isn't so much the death of the character but that characters impact once they are gone. What it does to the dynamic of the group as a whole. Granted, I leave death in RP up to the gods per-say - in other words - the dice. Most of my Rp's are set with some form of slice-of-life realism to them and in real life sometimes death just happens. There is no reason behind it other than death decided that day you are going to die. If your number comes up, it comes up. There is nothing around it. 

Sure certain circumstances will raise the chance that someone dies, so it is more likely to happen. For example in my Walking Dead and Darker Than Black Rp's - These Rp's are set up in such a setting that death is EVERYWHERE. They have racked up high death tolls. It's just part of it. (And the Rpers are very aware of that, most have multiple characters and back up characters ready to go) Getting killed is kind of just expected but it doesn't mean it hits any less hard than in an RP where death rarely happens. I actually have found that the long term effects for many in those Rp's becomes a pivotal part of the development of the story for those that survive. Sometimes everyone surviving is much less impact-full and believable than everyone dying. 

Now with other devices such as torture, rape, and so forth - it is a different story; to a point. I find that you don't have to do into grave detail about these types of things. You can Hitchcock it. (It happens behind the scenes, no one sees it or very little is seen.) Then again, it goes back to how that one moment play out in the long term. How does the characters mind change, how do they cope, over come it, succumb to it? How do their changes change those around them. 

In the end, these things can all be very effective tools for both character and RP development. Everyone is going to go about it differently, just as everyone goes about Rping differently. For me, it is more about finding like minds. Seeking out Rpers that are on the same page as you. If you can do that, then the skies the limits and tools are most effectively utilized.