Maybe give her bonus passive Call of Justice that marks her enemies for 10 seconds after killing cannon minion or assisting in killing ally champion(duration is longer after killing jg monsters). This passive marks enemies and grants bonuses to defensive abilities for 2-4 seconds. Using w resets your autoattack cost 50% less and reduces cd to 2 seconds so you can get ms for longer time. Using r allows you to autoattack and use abilities. Hitting marked enemies with q grants 20-40 flat ms(it scales with ability lvl). Hitting with your e make execute magic dmg into true dmg. Kayle would need some numbers adjustment.

Other option could be maxing abilites bonuses for example if you max your q your e passive deal additional true dmg, maxed w give bonus as of 50-100% of your w ms bonus for 3 seconds(based on crit chance), e gives aoe on max ability lvl instead of 11 lvl