For the people that might not have bought MK X or have not had chance to see it, the fatalities themselves really arn't that hard to execute. Below are two of D'Vorah's fatalities. You can also go into the move set section and have the fatality commands appear just below your name in game so you don't have to go into the pause menu.
Bug Me: (Mid) Bk, Fwd, Bk, X
Heart Broken: (Close) Fwd, Bk, Fwd, Triangle
I'm not saying this to dissuade people from bitching about buying 'easy fatalities' I'm jut trying to put it into context, they are not hard to do, it's not like people have to memorise 15+ button presses. I personally can't see the point in buying them myself and I earned two of them just wandering around the Krypt in my first play session.