I've always thought the whole tournament premise was kinda boring. It's the excuse for almost all fighting games. Kinda just the easy way out, I guess, but as soon the story starts to leave that premise, it starts to get more interesting too, imo.
Take Dead or Alive, for example. No good story mode in any of those games, however, there's a kinda interesting subplot with the ninjas and the main baddy Donovan that I think could be cool to be elaborated on. But 90% of the roster are just there to fight in the tournament, and... that's about it. No character development or plotlines, just people coming together to fight for a prize.
It's not good storytelling, imo. And though a lot of people say that fighting games don't need a good story, I believe MK has proven that not to be true. MK is not the best fighting game, but there's a reason why it's so popular even amongst people who don't really care about other fighting games. The stories, the characters, the world building etc in MK is just vastly superiour to any other fighting game, and I personally think there is enough material to create a large RPG setting on par with any of the Final Fantasy games (just to mention one of the more popular RPG franchises). In fact, I've made several campaigns that were based in the MK world and played through them with friends, both where they played some of the known characters and their own created ones.