Mortal Kombat faces the same problems as the X-Men and possibly the Avengers; how do you balance an ensamble cast? We all know the first 3 X-Men films didn't do a good job of that, but could the Avengers prove us wrong?
Any who the MK franchise is full of characters, but in order to pull off a good movie they have to pick and chose which characters serve the purpose of the story.
It's no brainer we'll see Lui, Sonya, Raiden, and Cage, but what about Kitanya, Jax, Kung Lao, and the other do gooders? How can you "re-invent" these characters? The first 2 films were a carbon copy of the game(with some changes), but what will be new and fresh to us, the fans? I think story is more important than who will appear. There's an ancient background of MK(Edenia, Outworld, ninja clans,etc) and the modern story...
How the hell did X-men not handle their ensemble well? At least the first two films anyway.