Tremor stuff #2
Gold Ball is good move in general to add to the kit, particularly for zoning. I like to throw out a gold ball here and there and let it recharge back to full bar for the ambush stuff. Ambush Gold Ball is excellent with fireball zoning and can be a decent thing to throw out after Injection. Basically just do anything, time the ambush low ball and continue your pressure.
Metallic FK has a few active frames and can be extra plus on knockdown while launching. Probably the easiest of his tools to get plus frames with and it launches(Not a combo unless ambush).
Aftershock BK can be a nice sneaky long range low but the ambush is particularly strong, again working well with his zoning in a midscreen range but also giving access to all these cheeky resets and pressure.
Tremor can ambush to make Young Shang claws safe like some other kameos. Metallic's FK or Aftershock's Straight Punch are always one switch away. You could also put up Crystal armor. You can combo from it the armors in the corner for like 220.
You can combo from Injection or EX Injection using Ambush Up Rock Punch or Metallic's options.
You can also use Tremor ambush to launch from a string while you cancel into Form Change or EX Form Change. Haven't found a great reason to use either this or the Injection one but I would think there's some good stuff across the cast.
You know that Crystalline Armor changes the hit reaction you take but you might not be considering that it prevents you from being captured or knocked down by projectiles. Stuff like Rain's Puddle and Water Gun, Scorpion Spear, Ice Ball.. all limited when you have that up. You can win more trades with fireballs.
Tremor has some of the projectile wall qualities that Shujinko has when you do Neutral K, although he doesn't stay on the screen for nearly as long as Shujinko might. But because he's standing, he can easily eat a hit of Kameo Lao hat or any other projectile. Another thought, since you can ambush from this, you can actually condition the opponent to be scared of it in general.
Shang's got a lot of things going for him even without Kameo like his consistent damage and fireball game and I think Tremor can allow you to attack the opponent in different ways that add to Shang's gameplay. The ambushes are 'expensive' and you can get yourself in bad spots if you use it the wrong time but I think you'll find yourself having a lot of options and some that are worth leaning into with Shang/Tremor.