Mileena
Mileena is another example of a fighter that was in the last two games, and unfortunately didn’t it to MK 11 to pad out a roster that desperately could use some padding.
Her situation though is a bit more unique than the other four fighters on this list. Mileena was properly killed off in the last game’s story mode. You could make the argument that there’s at least a narrative reason for her to not appear in MK 11.
That is until you remember that the story of MK 11 opens up a portal to MK 2 and fighters from that era pour into it.
Not only would it have made sense for Mileena to walk through that portal just like everyone else that did but unlike Reptile, who admittedly has never had a major part in the overarching MK plot, Mileena actually would have enhanced the story of MK 11.
In the last game Mileena was killed for trying to claim the vacant Outworld throne left by the death of her adoptive father, Shao Khan. Having Mileena team up with her father in the present in opposition to Kitana and Kotal Khan would have been an awesome moment.
It still worked out fine, the story in MK 11 is great regardless, but seeing past Mileena and Kitana go at it again for supremacy in the present would have been a neat angle.
