He's on the disk as a NPC (without variations) without any new moves. He's a re-skinned MK9 Rain. They put the time and effort to involve him in the story (and not kill him horrifically so we can see him in a future game as a cameo that dies by D'Vorah). His involvement in the story and his re-design is a big deal for Rain fans because this will easily be one of the best selling MK games and it'll only give him more fans. Of course I would want him on the main roster, but this just hypes him up for when he does appear.
In terms of NPC appearances, Rain and Tanya received the most amount of attention. Fujin, although not being able to fight him, survived and looked badass in the chapter he was featured in, so he is next. Baraka, although you get to fight him, was just in a flashback and was embarrassingly murdered. Frost barely received any attention and was, like, frozen and forgotten about (she also just had Sub-Zero's costume). Li Mei, Bo' Rai' Cho and Sareena were pretty cool, with good designs, but had little involvement in the story. Hell, can you imagine if you were a Sektor or Reiko fan? @__@ Now that's a slap in the face (although Jade and Cyrax fans always deserve to be livid).