I liked Shinnok in Armageddon.

The thing about him is though, he's the Emperor from Star Wars. His thing is the planning and the manipulation. Nobody's scared of the Emperor, they're scared of Vader, cause Vader's the big tall dude who does the fighting.
What you're looking for, though? Being scared of the boss...that doesn't exist. It's not possible. Not in a fighting game. Not for a grown adult. A survival horror game or zombie-themed FPS, maybe. it's nearly impossible to feel fear at a fighting game boss though. Difficulty isn't scary. "Scary" comes from sudden surprises, musical stings, and gruesomeness.
Personally, I thought Motaro was scary when MK3 first came out...but I was like ten years old and he was a creepy lookin' monster. Never felt a single bit that way about Goro, Kintaro, or Kahn, because they looked more human, even though I never beat Kintaro but I could take the others. So obviously difficulty had very little to do with it.

To be honest, Shinnok is one of the characters that has my green light still (Not trying to sound pretentious) I don't get my hopes too high for the future of this franchise but for him in particular since it seems given that he'll be back. I could be disapointed of course.

Like Razoredge said, i'm not expecting to be scared by Shinnok, or impressed at all. But Onaga and Blaze remember? Onaga had the look i'll give him that much but once you started to understand his pattern? He was a really easy boss. Goro scared me when i was a kid and still, a couple non boss or sub boss chars still have that potential to be scary or do scarier stuff. Just Shinnok? Some ppl talk about bringing back his demonic form from Mythologies i guess. With better graphic and a better arsenal of moves that could do it for a boss. Guess i really like Shinnok mostly for what he could be than what he's been so far.

Mortal Kombat sucked all along in terms of boss fight though. And Kahn in MK9 is no different. To be honest, some of the other chars would still be better bosses than the bosses we had yet if we keep in mind that Shinnok was as big and as easy as Jarek in MK4. Still, until they bring a new boss, i really think that he can be the big evil this time.

I think maybe I said that wrong. I didn't mean to be scared of the boss as in he'd give me nightmares, but rather worried that the boss is capable of giving me a good beating or at least a challenge. Onaga was very tough at first, Moloch also could deliver a beating. Neither the Shokans or Shao Kahn gave me any worse of a fight than the average non-boss characters. I don't think it's too much to ask for a boss that is a tough cookie.

Shinnok is one of my favorite characters. From a gameplay point, you will always find ways to beat bosses. So they're never really threatening. As for the story aspect, Shinnok is great. I think he is way better than Kahn. Shinnok is a clever guy who much like Quan Chi does his work from behind the scenes.

Shao Kahn on the other hand is rather boring. He uses his brute strength all the time. Never has any ideas of his own. I like the fact that Shinnok wasn't like Khan. He didn't need to lumber over the opponent to be a boss. Sure, he was a weak boss but I'm sure if they gave him his own moveset for MK4 he would've been more difficult. Anyway that's all I've got to say.

@beautifulprincesskitana

I don't know yet. Big bosses are not guaranteed harder imo. Since Goro, the hardest bosses i fought in MK were the Noob/Smoke team from MKD and Quan Chi and Shang Tsung from MKDA. Quan Chi had that double broadswords that would sometimes hit even when you would do a sidestep and also had that power up feature to enhanced combo strenght. They were way more challenging than a big, cheap boss since with most of them there is a way to turn cheap on them and spam the same shit over to kick them all over the place.

Night Terror from SC3? The long range chars like Astaroth or Ivy would provide you with a better chance to ring him out and get extra damage so he was kind of hard to defeat for 5-10 minutes.

Shinnok is still an unknown potential even though i agree that each time he's been a boss he ended up pretty easy on the side of difficulty but his MKA appearance was not so bad. He was just not equipped with any powers stronger than any other char like Scorpion or Sub Zero for instance. And you could perform a throw on him unlike Goro or Onaga.

He could end up as a challenging character even if he remained normal sized, just provide him with bigger damage and more imposing set of moves i guess. If he gets really big? I have a feeling this is where the cheapness will start to show. This is still just potential but i think he's got way more than Kahn.