Like a lot of the comic book films, and even other video game franchises, these films really should be brimming with special features.

Some of the obvious inclusions I'd love to see would be some of the FOMA clips, audio commentaries with the director as well as another track with Boon and the gaming side of things.
There's really plenty of material for featurettes, ranging from game-to-film comparisons, and then general game stories. We sort of got a hint at this kind of stuff through MKDA, but really there's obviously A LOT more to the story, and it'd be great to get some kind of insight into the evolution of the characters and games.

Then you've got your standard movie fare. Interviews, and making of featurettes.

It'd be nice to see something solid.

Also, clearly with the first MK (and probably the second) there's a decent selection of omitted material, be they straight-out deleted scenes, or original versions of scenes.
It'd be particularly interesting to see original scenes featuring things like Scorpion and Sub-Zero flat out being allies.