The roster will end up being fine. People forget about the DLC and what not. Here's my prediction for the final roster (including the first 6 DLC included in the premium edition):
Scorpion (confirmed)
Sub Zero (confirmed)
Skarlet (confirmed)
Sonya (confirmed)
Raiden (confirmed)
Geras (confirmed)
Baraka (confirmed)
Kabal (confirmed)
Kano (confirmed)
D'Vorah (confirmed)
Shao Kahn (confirmed)
Cassie Cage (Already shown on the menus with a redesign, mentioned in dialogue)
Kitana (Already shown on the menus with a redesign, mentioned in dialogue)
Rain (Already shown on the menus with a redesign)
Noob (Already shown on the menus with a redesign)
Shang Tsung (Massively popular character that sat out MKX. No chance he's not in)
Liu Kang (He's Liu Kang)
Kung Lao (He's Kung Lao)
Kenshi (I just think he'll be in)
Kotal Kahn (One of the best newcomers from MKX, he needs to be in)
Human Smoke (Massively popular character that people want in human form)
Sindel (Haven't seen her since MK9 and people love Sindel)
Fujin (Easily the most requested character since DLC for MK9 was announced. Absolutely in.)
Jade (Another much requested character)
There's your base roster. First round of DLC will be as follows:
Mileena (Way too popular not to include)
Ermac (Again, way too popular not to include)
Khameleon (Just a feeling I have)
Sareena (Will be added as DLC a la Bo Rai Cho in MKX who was in the story, but not yet playable)
Spawn (I don't care about him, but people have been begging for Spawn forever)
Pinhead (I honestly have no clue)
I'd be willing to bet this roster is about 85-90% correct.