This is an older thread I know but I only recently made an account so...
If you are still playing Liu Kang after the recent nerfs his cancels are going to feel very off putting, just as A-List players feel I assume. When I first picked up Liu Kang, I found that my biggest issue was that I would input the cancels as such: F123 BF1 FFR2 F123 when in actuality you do not have to press forward twice and instead you can input it as F123 BF1 FFR2 123, holding down F from the second input of the run. I'm an unaware as to whether this is common knowledge but I know that is what always held me back. Secondly, the buffer window for cancels allow you to put the run input earlier than the fireball animation. If you were to input F123 BF1, and then quickly input the run without inputting any other inputs, you will notice that after a short pause, Liu will run despite you not inputting the run when he starts the running animation. I noticed that this especially helps with D'vorah's cancels. This delay will give you a reprieve as you orient your fingers from the run input to the 1234 inputs. Once again I am unaware as to whether this is common knowledge or not, but I thought that I would share how I learned them.