Kai' Sa isnt weak.

Kai' Sa isnt weak. People just think she is this revolutionary adc where they trying to build her hybrid to make use of her ap scaling but still play her like a crit adc or other adcs who can thoughtlessly use their ult at any moment. With Kai' Sa's passive she doesnt need a damage ult. Just ignore her ap scaling build her crit like any other adc with a lifesteal item stand back and spam autos and q due to her q i would ignore Infinity edge until after Essence Reaver. As for when to ult only use it after you have already won the fight and you cleaning up people who are 1-2 hits from death who trying to run away. The other and best use for her ult is for when you get dove by a fighter/ assassin to use it to gain a sheild reposition and cause them to miss their skillshots and kill them in 3 autos with your crit.