How do you do it then? You use the fixed target bronze indicator?
Enemy in front of my character, with my character turned toward enemy, camera behind me facing directly toward enemy, hitting immobiled target or target attacking me or otherwise stopped / busy in an animation. I do not attempt to attack moving targets with it. If I am using it to lunge across the screen, I follow up with a combat roll and attack cancel x2 before deciding to either move, CR, CB or MB next. Especially true if I am whiff-missing after the PS lunge. However, the point of the lunge wasn't necessarily to hit, but to glide across the screen immediately.
I don't have video of you missing, so I cannot tell what you're doing wrong, but I do know what to do to make it right, and I listed the qualities above previously.
Were you on host or off host? Were you using cycle target (or right mouse click) for a yellow-brown target cursor (instead of white)? Were you facing toward your enemy with the camera? Was your character facing toward the enemy? Was the target moving at an oblique angle to you? All these factors affect targetting accuracy for all abilities that track, PS included.
On host rocks, off host sucks. Hard target via cycle target (default tab on keyboard) is ideal, though not always an option for time (helps a lot though for bigger / boss targets, can cycle on approach). Camera orientation always matters. Character orientation matters. Character positioning matters. Target positioning, vector movement and direction matter vs character vector alignment. Range matters (again with positioning).
PS + other Melee skills are awesome, but you do need to learn to use them. I don't know how you're using them and failing at them specifically, but those above are all things I've learned to take into account and adjust for. If you want to make a video of how you're failing at it, I can point out why you are, but it is probably best if you begin to learn the habits of manually orientating your camera toward your targets and using cycle target for a hard lock, while adjusting for spacing, movement and timing.
-- and noobs say Katari & Perilous isn't about skill. Ppppbbbbt.