Next to no anti-airs(Kung Lao has the best anti-airs)
Best D2 in the game isn't a good anti air, is it? Kung Lao needs meter for his EX spin. His normal spin gets blown up by things that Liu Kang's D2 destroys, every time.
God awful air-to-air game (Kung Lao is easy top 3 air-to-air)
Liu Kang has instant air fireballs. If you're jumping at people with jump kicks and jump punches with Liu Kang, you're playing the character wrong. He doesn't need to engage in a close air to air battle. Play Kung Lao and jump at people with his jump 2. You'll lose almost every exchange when you're in range of their jump punch, even vs Liu Kang. His J2 has a 10 frame start up. You'll see the best Kung Lao's jump back with his J2.
I know Kung Lao gets a full combo off of his jump 2. I'm just trying to shine light on why Kang isn't weak in these areas. Not downplaying Kung Lao.
A neutral game thats not even half as good
How is his neutral game not good when he has great projectiles? Projectiles are great at dictating the neutral, especially when you can do instant airs that shutdown jumping. Lets also not forget that Kang has top 3 movement speed. Advancing mids aren't everything on Mortal Kombat X. Shinnok is supposed to have some of the best spacing in the game. Where is his 11 frame or less advancing mid?
Lack of armored launcher reversal (Kung Lao has arguably the second best one)
To throw out your "Kung Lao has arguably the second best one" argument right away, EX flip kick and EX punch walk. Obviously there are a few more that have a case for being better than EX spin, like Tremor's EX shatter in Crystalline that's + on block. You can blow that up, though(still, + on block lol). EX flip kick and punch walk on the other hand cannot be blown up(i'm sure something that isn't practical might be possible) and are safe. If you debate that EX spin is better than either of those moves, well.
I don't play Liu Kang, but I believe he has a few armored moves that are safe on block, right? So instead of an armored move that's incredibly punishable, he has a move, or moves, that can't be punished. The trade off is that they don't launch. Although, even on block a mind game is opened up, and on hit, Kang gets his pressure. Not saying this should be preferred in Mortal Kombat X over a very punishable armored move, even though it might be, but it's not that bad of a deal.