And lets have a civil discussion about why. I want to start off by saying that we don't KNOW the roster. We have seen a convincing rumor that hasn't been wrong yet.
So let me play devil's advocate for a minute. We don't know for certain that Goro will be sitting in that roster spot, but for now lets assume he will. We know that there will be a secret character in story mode. Chances are, that character will share a spot on the select screen with Goro and the DLC, just like Cyber-Sub did.
As for that character's identity, we can safely rule out Shinnok and Liu. I don't think we'll have any revealed characters locked out on day one. As for the remaining unrevealed characters in the leak, we are left with the Briggs', Sonya, and Kenshi as potential unlocks. Again, unlikely, and they'll probably all be playable right out of the box.
So who are we left with as potential secrets? I'm going to say right now, it's not another Revenant. We've seen all of the ones we're getting. All of the playable revenants are in costumes designed from the ground up, all of the others are in updated MK9 gear. Scorpion is a special case, because he has a canon reason for those clothes, I guess.
Fujin and Rain seem like safe bets. Cyrax is another possibility, given Boon's "late to the bus" tweet, and his tournament popularity. A week ago, I might've thrown Smoke into the fold for that same reason, but seeing him in story mode has me skeptical. They could bank on him as DLC later on though. Another fan favorite theory is Frost to fill in the Lin Kuei and round out the Next Generation theme. I'm not too sold on this one, but it's worth mentioning. Then there's Baraka (confirmed to now have face spikes by his statue in the Story Mode intro), and Reiko and/or Havik, whose most likely scenario for inclusion would be as the "surprise returning" boss.
In reality, we don't even know how many hidden characters there will be. We could get hidden characters in the living tower, we could get them as faction unlocks, we could even get them from the mobile game. At this point, all we know is that there is at least one in story mode. So what if. WHAT IF it wasn't the roster that leaked, but NRS's prerelease schedule instead. The secret characters will probably all be shuffled into one slot anyways. If someone got there hands on the prerelease schedule, it wouldn't be hard to connect the dots on the roster spots and call it a day. It seems pretty clear that we're going to see everyone on that list before the game comes out, and we have been told that they aren't going to reveal everyone before launch. You do the math.
TL;DR occam's razor would suggest that there are more characters in the game than we are currently aware of. Of those, the only super likely ones are Fujin, Rain, Baraka, Havik, and Reiko, with Cyrax and Frost getting honorable mentions.