My guesses for the roster,returning(MK9) and new:
Raiden (May be unplayable)
Johnny Cage (Semi-Konfirmed,one of Cassie's parents is appearing)
Sonya (Semi-Konfirmed,reasons above)
Baraka (He lived)
Ermac (He's awesome...i mean he lived)
Reptile (He lived)
Scorpion (Konfirmed)
Sub Zero (Konfirmed,may be Bi-Han if he survived the soulnado)
Mileena (She lived...i think)
Cyrax (He...lived?)
Sektor (He lived)
Quan Chi (Konfirmed appearance based on MK9's ending,may be an unplayable boss)
Kano (Where the hell's did this guy go?Let's assume he lived)
D'vorah (Konfirmed,i woudn't make up new kharacters)
Ferra & Torr (Konfirmed,was at E3)
Kotal Kahn (Konfirmed,we need someone with the surname Kahn)
Cassie Cage (Konfirmed,every game needs a badass cop)
Reiko (Not konfirmed,still he's part of Shinnok's army)
Shujinko (He revived Onaga,in 25 years he must appear)
Taven (Same reasons as Shujinko)
Daegon (Reason above,May be unplayable)
Fujin (He's a god and he's been in MK4)
Now for possibly unplayable/playable bosses:
Shinnok (Konfirmed by MK9 Ending)
Quan Chi (Konfirmed by MK9 Ending,may be playable)
Onaga (Revived by Shujinko,as he still exists in the timeline)
Blaze (Possibly defeated by Taven,there's no Shao Kahn in the way this time around)
Surprise Returning Kharacter (Konfirmed by Ed Boon)
People that have a chance but i'm not placing any bets on yet(MK3-MKA):
Ashrah (Never played as her,still there's nothing against her appearance)
Bo' Rai Cho (I don't really know why,same reasons as Ashrah maybe)
Dairou (I think he's kinda boring,still Boon never said he woudn't appear)
Darrius (Same reasons as Dairou)
Havik (If done right,he could be a great kharacter)
Hotaru (If he appears,Dairou appears)
Kenshi (He was DLC last game,it'd be cool to have him integrated in the story)
Nitara (She serves the Dragon King,if he's in,she's in)
Rain (He's Rain,people like him)
Skarlet
Tanya
Unlikely to appear(Doesn't mean i don't want some of these guys):
Chameleon (Most fans consider him a joke,i like him but still...)
Drahmin (Konfirmed by Ed Boon,he isn't appearing)
Frost (Just a replacement for Sub-Zero,nothing too great about her)
Hsu Hao (Konfirmed,i mean everyone hates this guy right?)
Jarek (He was just a replacement for Kano last time,i hope he has a chance)
Kira (Replacement for Sonya and Kano,same reasons as above)
Li Mei (Deadly Alliance didn't happen,she has no reason to fight)
Mavado (Konfirmed by Ed Boon,is someone gonna miss him?)
Meat (Wish they gave this guy a chance)
Mokap (Konfirmed,who the hell even likes this guy?)
Moloch (Konfirmed,no Deadly Alliance,no Drahmin/Moloch kombo)
Khameleon (Same reasons as her male counterpart)
Kai (No Liu Kang,small chances of him appearing)
Kobra (Was never such a popular kharacter,still nothing's stopping him from appearing)
Sareena (Same reasons as Kobra)
Now including everyone but the unlikely guys we get a roster of 36 kharacters,it's a pretty good deal in my opinion,but we may get a smaller or a bigger roster.Ed Boon already konfirmed in an interview that we're yet to know the roster size and the real kharacters shadow so i guess some of this predictions can actually come true.Of course we could get some of the unlikely guys too,maybe even more new kharacters?So what do you think?There's something you wanna add?