Let me break some of these down:
Ermac - He has a teleport. And it's not hard to react to a missed up/ground/straight ball that's whiffed and go from there. Ermac's normals are also better. Upball will not always track teleport and if you miss just 1 ball, you are eating a lot of life.
Reptile - I want to meet ANY Shang player in the world who can keep out a good Reptile. He still has acid spit which is crazy fast. I promise he will get in and then the round is over
Scorpion - He can not only get in and create pressure SAFELY w/ex teleport, he is at + frames now on block. All Shang needs to do is miss one fireball. Scorpion is one of the best punishers in the game, and Shang gives him lots of opportunities. Plus again, Scorpions 1 series is one of the best strings in the game for up close pressure. Scorpion will build meter very fast and continue to safely teleport in w/ex teleport
Noob - He's got a teleport on any whiffed ball. He does not have to sit there and respect Shang's zoning. Once he gets the life lead, he can out zone him
Kano - Knife is one of the best projectiles in the game and can easily air ball over a whiffed projectile. Also has good up close pressure
Kitana - She can get around the zoning AND her d1 is pretty dumb that yet again, Shang can't deal w/. Shang, like these other matchups, will be doing nothing but taking risks this entire matchup. The skull will not always track her air wave.
Ermac: He has bad normals because he has no mix up game. His teleport is easy to read and very risky because it is punished by full combo. These matches usually require Ermac to dash block in to mount an offense or try to catch Shang with a force push. Shang wins because he forces Ermac to come to him. Last time I checked, Ermac doesn't have an upball.
Reptile: It is a tricky match, but his main tool is the dash. Like most projectiles, the acid spit is tradeable with ground skulls. If even one of his projectiles trades, it usually leaves him on the far end of the screen, which is not where he wants to be against Shang. He can get in, but this can be dealt with by punishing the dash and using skulls to keep him grounded and at a frame disadvantage.
Scorpion: He is 5-5 with almost everyone in the game because he lives on 50/50s. Again, a teleport is not a win button against Shang. His EX teleport (and regular for that matter) is interruptable with a D+1, or at last resort, allowing him to land the second hit to take away the safe jump. Both players have to guess, so I wouldn't say that one is at a disadvantage.
Noob: More guessing. If he guesses wrong and anticipates a ground skull with a teleport, he will eat a combo. Even one connection with a ground skull will lead to an unbreakable combo. Noob only gets really dangerous if he corners you, which is due to Shang's poor wakeup game.
Kano: He has to be at about mid range to be really effective. Full screen, Kano and his knives get destroyed because the skulls cause a knockdown. All of his balls are punishable. Pre hotfix, this was in Kano's favor. But the added knife recovery and punishable upball have really weakened his game.
Kitana: You can make her think twice about throwing fans or abusing d+1 beacause of the ground skulls, which will check her on the spot. To punish the wave dash, you must time the upskull to when she is above your head. Shang can more than deal with everything that she has.
What you seem to be marking Shang down for is his reliance on making good reads. Yes, some characters have more room for error (Lao's abusable spin), but that does not mean that Shang can't be competetive. If you can get a feel for what your opponent likes to do, then you can keep them guessing. He has an answer for almost everything provided that you know your matchups.
. I also can't see the vid you posted cause I'm at work
