well... it depends~ CK is not 100% that give you a score. it just increase the chance (and it also depends on player's skill) yea PK also can be a good CK taker~

but i prefer that CK are in ST or AMX (X= R,L,C) because they are lack of defense skill...which means they have higher crossing, and passing skill in attack... while PM i prefer in my MC which the skill are average....so... that means their attacking skill are lower than ST or AMX in my team

I disagree: I'd rather my DL or DR have Corner kick ability because my AMX's as you say are better at attacking and therefore scoring goals, especially if they have dribbler or shadow striker. Plus, After corner the play stops and takes back, which means your DL or DR will be right back in his place (so unrealistic, I KNOW!) but better they have a CK skill so all your attackers can have a chance at scoring DON'T make your DC into CK, they need air defence