My ideal MK11 roster is as follows (you may not agree with it, but it's what I'D like to see).
It's a mixed bag of what I want and what I think will be the roster, due to either fan complaints if certain characters aren't in or because they are established in MKX as being obvious for the next game:
1. Scorpion - fan favorite, people will cry otherwise
2. Sub-Zero - fan favorite, people will cry otherwise
3. Raiden - Dark Raiden at the end of MKX hints at him being back for MK11.
4. Liu Kang - I don't care whether he's in or not, but it seems that he and Kitana will be the new NetherRealm threat.
5. Kano's son - Would be a nice replacement for Kano (IMO), at least for a few games. Kano doesn't have to die necessarily, but it would be nice for the next generation to take over.
6. Cassie - Johnny and Sonya can be cameo characters (like Li Mei, Fujin and Bo Rai Cho were in MKX) for the next game.
Again, Sonya and Johnny don't need to be dead, per se, but I'd like to see them sit out for a bit, maybe as cameos.
^^That pretty much covers MK1 and their descendants, for me.
7. Reptile - Usually doesn't miss MK games, and he's another character that people would cry loudly for, if he isn't in.
8. Kitana - Same reason as for Liu Kang
9. Kung Lao - I don't care for him, but people will whine if he's not in, so he'll most likely be there.
10. Jacqui - Can take the "Jax" role for a few games, with her own moves, so that she and the other new-gen characters can shine for a bit
11. Takeda - Would be nice to see him return to MK11.
12. Kenshi - I doubt that Boon will get rid of his 2nd favorite any time soon.
13. Kung Jin - Again, if it wasn't for people complaining about Kung Lao not being in, it would be nice to see Kung Jin take his place for a few games.
14. Kotal Kahn - Would love to see him return
15. D'Vorah - Great villain, IMO, and I'd love to see her in the next game.
16. Erron Black - Great character, but I feel that he lacked story and hope that they can further expand on him in the next game
17. Fujin - Fujin is LONG overdue in a current-gen MK game.
18. Reiko - Same as Fujin
19. Havik - Same as Fujin
20. Shang Tsung - Shang Tsung being a villain on his own and not being someone else's puppet would be nice, for once.
21. ???
22. ???
23. ???
24. ???
25. NEW
26. NEW
27. NEW
28. NEW
* Sadly, I don't think that enough people like Ferra / Torr to see them return.
I'd like to see them return and I think that their story and lore could further be expanded upon, but I don't get that feeling from people, in general.
** I left the 4 ??? spaces for interchangeable characters like Smoke, Kabal, Noob and either Cyrax or Sektor, which people will want back in the next game.