#1 MORTAL KOMBAT 10 - A direct sequel

Shortly after the events of Mortal Kombat 9, with so many heroes dead, the Earthrealm is open to attack by Shinnok's forces. This means we would have Raiden, Sonya and Cage teaming up with "new" Earthrealm heroes such as Kenshi, Kai, Frost, Li Mei and Shujinko.

I think MK9 did a great job of revamping characters who weren't well liked in previous games (ex. Stryker, Sheeva). So we would have a ton of characters from the MK4-DA era who would need to be revamped and then some new characters to freshen up the roster.

#2 MORTAL KOMBAT 10 - All new game

Boon and team take the game in a completely new direction with 2-4 familiar faces (Scorpion, Sub-Zero, Raiden, Sonya) and the game features all new characters and a new storyline, maybe set in the near future? They should base the new characters on familiar races as a nod to beloved characters (a cyborg, a Saurian, a sorcerer etc) or explore other species seen in the MK universe.