...Basically all the classic versions besides the PSX and arcade ones, sucked, because blood was removed/dubbed down.
I think the gameplay is pretty smooth. I play MK: Deadly Alliance and it's pretty smooth. It has features such as switching fighting styles, and you actually have to work to get secret characters and loads of other bonuses. If anything, it's far from simple.
Fatalities purposes are to simply, I don't know, kick their ass in the awesomest way imaginable?