The worst thing going for kids right now is the speed of today and the desensitization to violence. Right now, the internet and the sharing of information are two very large things that have happened in the past, and right now I would make the claim that this is a fairly large part of why the youth of today are so violent. Another reason is because parents are at work, and kids don't really have anybody to tell them when and what they are doing wrong.
OT: What will be the problem tomorrow? Probably social disconnection. I'm not really sure, but I think Social Disconnection will make human beings violent, because we aren't used to that, and right now we are the most socially disconnected society since like ever...
EDIT: I didn't clarify my Off topic statement. When I mean the speed of today, I mean how fast we expect everything to happen. I don't know about the teenagers of the past, but faster = better in almost any teenagers mindset, and that's grossly untrue.
Sharing of information means sharing of ALL information, even the bad stuff. If someone is subjected to violence enough, and isn't taught every single time that it is negative, the person will be desensitized to the violence at hand. It will happen because humans are adaptive. Especially in this age of gaming where not only are you not punished, but you are actually praised for killing people in-game, that if you are NOT taught morals like you should have when you were a kid, you will think that violence is what's right a good.
Which leads to my last point of not enough parental involvement. Yeah, if you aren't taught AND disciplined on the morals, you just don't have a grasp on what's violent or not. More and more cases of kids killing other kids end up with them basically saying "I just wanted to see what it really was like." They don't have concepts of life and death, because you can just hit the ESC key and load a save, and then nutshot the guy you killed with a grenade fist or some shit. I mean, I think it's fine to play violent games; I play them as much as anyone else. I was also taught morals, and I had Parents to tell me when I did something right and punish if I did something wrong. Also, I was taught courtesy, which goes a long way in preventing violence. Something that a lot of younger kids didn't seem to learn.