I don't agree with the term "wasted spots", but I definitely think Kitana, Kung Lao and Liu Kang shouldn't be in this game. Those primary costumes should be alternates. It's an inconsistency for sure. People then say Noob, Smoke or Cyrax should be in the game instead of them, but they'd be just as wasted in my opinion.
Then, of course, considering the roster lacks villains, they added FOUR NPC in the story mode you fight twice: Baraka, Sindel, Tanya and Rain. Mortal Kombat X just felt very random and inconsistent all along.
Don't give me wrong, this story mode is FAR BETTER than MK9. While still corny and cheesy, it's also much more serious with a more solid plot than MK9 ever tried to be. However, it felt short, much shorter than MK9, with many lose ends. They could have added more chapters for sure, but then again, what villains would you fight? They killed FOUR of them in the story: Baraka, Mileena, Quan Chi and Shinnok (kind of). Kotal and his forces were definitely neutral, Scorpion and Sub-Zero ended uo being good guys too. Only Kano and D'Vorah ended up being the only true villains alive.
I actually loved the ending, I guess I am the only one. My question: will Cassie and Kenshi's endings be cannon? I would like to see Shujinko and Daegon again. Daegon in particular I feel has lots of potential. I guess Red Dragon is dead.