About the whole Killing everyone and being totally normal with it. Is it possible for someone to be able to do that, yes. It's possible. Can it be conveyed properly in RP form. That's a whole other topic right there. There are just some mental states of mind that are unfathomably difficult to write for; can people do that properly, maybe. Maybe. Will the majority of RPers who make insane, super cold blooded killers who go back into normal super friendly mode after a killing spree; be able to write them properly. Probably not. 

It's a different mindset, and there are talented RPers who can do it right, but it isn't for everyone who just wants to be edgy or unique. That's why Character Sheets and A Sample post would weed those out. The RPers who can tackle those types of characters properly will shine through. It's the same deal with Uber Characters or Ninjas. Not everyone can play those types, and if you want to help someone try that's fine but in the end it's the decision of the GMs to allow those types of characters. Those are my thoughts on the matter.