A lot of times water retention is blamed when the athlete just isn't lean enough. But in this case Kai missed top form mostly due to water IMO. Look at his face, extremely round and it isn't fat (extreme anadrol and test intake). His whole body looks soft and the diuretics just made it look worse.
I agree with tbombz, Kai has a type of muscularity and pop to his physique that's best on stage in many ways.