They're two completely different games. One should not rip you apart from the other unless you aren't an MK fan and you just don't appreciate the game anymore. I am definitely an MK fan so will I drop MK for Injustice all together? Fuck no. Will I play Injustice more at the moment because it's a new fighter that's interesting to me? Of course. Injustice should not replace MK in the slightest. Two different games, way different mechanics, all different characters and stories. I'll be supporting both until they die.