Why I think a multiple story arc would work best is that Mortal Kombat really isn't about any one particular character, each character has their own journey, each of which could be it's own film, so why not do that except scaled down? If you go the multi story arc route you can cover maybe 5-6 characters, say Liu Kang, J. Cage, Sonya, Sub-Zero, Kitana, and Shang Tsung for example, each of those mini stories could overlap at various points leading up to the finale. I'm thinking of an Inglouris Basterds type scenario, that film has 4 different stories that all converge at the end, I think something like that could be possible here.