If they're really making another Kombat Pack, I hope it includes not a single MK 9 character. There are plenty of interesting characters we haven’t seen since Armageddon that deserve a place in the spotlight. Popular characters like Jade, Kabal, Sindel or Cyrax will always come back. But for Fans of characters like Daegon, Ashrah or Shujinko a DLC might be their only chance to play their favorites ever again.
I disagree with this, actually. If the intent is to just include underused characters for DLC and forget them again in a future instalment, then hell no. We need more DLC characters like Rain, Tanya and Kenshi and less like Skarlet. I would be extremely disappointed if they ignored Tremor for MK11, especially with all the Dream Realm hints and Mileena coming back to life because of it (watch his intro with Mileena). I'm saying this as someone who does not like Tremor.
If they want characters like Ashrah, Havik and Hotaru to be liked, they have to spend time on those characters. Good characterization involves the viewers getting to know the characters and becoming attached to them. Please don't say "it's just a video game", because it's not, at this point. The comic does very little to help this as it's amateurish and borderline insulting to the fans, at times. At this point, most MK fans don't remember any characters before MK9, so it's basically like they're starting new with these characters. Considering how much of a fantastic job with most of the new characters in MKX (Erron Black and Ferra/Torr were pointless. Erron looks badass, so he'll likely get a pass, but if Ferra/Torr don't appear in the next instalment, they'll get forgotten) I believe NRS can turn any character into something worth playing.
Sindel, Rain, Baraka were all fightable and had dialogue and plot purpose in the MKX game. Sindel and Rain had more of a purpose than a lot of the other characters that were playable even. So, all three of them, I think, stand the best chance. Fujin is easily the most demanded DLC character. To deny people again would be pretty awful. Sareena was very similar to Fujin, in that she was featured in a cut-scene, but doesn't nearly have the fanbase. If they included her as DLC, I'd be OK with it, since she seems to have a purpose now (sort of).
In an ideal world, I would love to include characters that were forgotten with their own story chapter. Characters like Sektor, who did not receive the proper send off, Reiko, who should have had, at the very least, a flashback inclusion in a Mileena POV chapter, would be my top two choices. This will never happen, however.