Liu Kang is just weird
he doesn't have many super high damage KOMBOS from what I know but he just can do a short kombo of of everything.
Subzero has a worse kombos than raiden but has way better defense as his ice flask can make him very hard to approach and any obvious attack can be countered by his down special and lead to a full combo (and he has a bit more hp).
I don't guarantee the game is really balanced though but its not an esports lol.