Board Thread:Mortal Kombat X/@comment-4222221-20140620035906/@comment-5901324-20140814024300

In this list not. Because the characters you said were never in the game in first place (except Tremor). Lets take a look on their situations:
 * Belokk - Completely removed from MK4 for unknown reasons. If it was time issues, he has chance of returning, but if it was a problem with the concept, he may never return.
 * Hornbuckle - Since Blaze, who was fighting him, became canon, who knows? He surely has chance.
 * Nimbus - Was, actually, an April Fools joke, and he doesn't seem so popular among the fanbase.
 * Tremor - Relatively popular, but it seems Ed Boon wants to forget about all related to Mortal Kombat Special Forces. I wouldn't discard him, however.
 * Hydro - Though no canon, including him as a playable character would be interesting, I don't doubt the current Sub-Zero is him.