I am very disappointed with the way the story turned out. Yes I agree; MK9 was not a masterpiece but overall the story was much better in both depth and length-wise. I felt as though MKX's story felt very lackluster at least to me. This is probably because after playing through MK9's story mode, I had high expectations and you can't blame the one's who had the same expectations as I. NRS has knocked it out of the park twice with the stories in MK9 and Injustice. Sure it's arguable whether or not Injustice had a good story, but I think it was decent enough. MKX had a lot to live up to, the one thing I truly enjoyed in MKX's story mode was the voice acting and cinematics.
I personally wouldn't like if NRS added an expansion DLC to the story mode because I'll feel like at that point they purposely stripped parts away from the story mode in order to charge us more money, but I love me some MK, so I'll definitely purchase it.