He obviously is imba, but what really makes him broken is not his perfect pressure game, and that he can steal you 23728382372737 turns, but how this character is make, to have a easy day at the office. Let me explain what i mean:
He have the best FB in the game, hands down. Has good range, its very fast, his FB have hitbox issue and can hit you even from behind. It has the best damage scaling, the moment you are bringing his health down to 30% is the moment you die. Its easy 40%+ damage, cause he just need 1 hit confirm and he will FB and you lose the round, he can land his FB late on the combo, and because of almost non damage scaling he can drain you for 55%+.
And what the funny part is, smart Liu Kang player condition themself to his KB and in the decisive game, they are going to drain your health pretty fast, pretty easy.
They most likely will have 2,3 or 4 KB, that are ready to go, because the condition for them is super easy. They will have KB ready on his Bicycle Kick(you cant brakeaway), he will have his KB ready on a throw, and if thats not enough he have easy to get KB on his High Kick on his F4 combo, also on his Flying Dragon Kick, that is a completely broken move, if you take into the consideration he also have the best zoning for mixed character. No need to mention he have KB ready to go on his parry move as well.
Rewind is a great player, but untill he switched to Liu Kang in MK11 his result suck**** hard. He switched to Liu and results start to coming.
People were complaining about Cassie, but she doesnt have a f**** whole screen anti air, anti zoning tool, she doesnt have imba FB, she doesn`t have such high damage potential, and she had like 1 or 2 useful KB, that was not big damage, and you could not combo on them. Also her so call annoying "low" shot was actually mid, and you can block it by standing.