As we've seen so far, the Pulsefire skins seem to be exclusive for ADCs presently. It only makes sense that fans want to see more. Reddit user VladBacescu did just that with an amazing Jhin concept to scratch their itch for a more futuristic, robotic version.
By adding this, Riot gives Caitlyn another villain to chase and Ezreal either a friend or a foe. It may force another Pulsefire Ezreal update, maybe even a Pulsefire Caitlyn one. If the Pulsefire line is not exclusive to the two ADCs, it only leaves room for ADC fans alike to cheer for cool, new skins.