I don't think it's a great idea to make Smite deal instant true damage to champions

One of the new jungle items in patch 4.20 allows Smite to deal 28-164 true damage to a champion. Instantly. Through all CC... Imagine a clutch play, where an Irelia is being chased. She dips out of the fog of war with very low life, turns on her pursuer with a stun, and life steals enough to win the duel once they escape the stun. This is a healthy play that is core to a bunch of kits such as Irelia’s and it already has a lot of counterplay: throwing skillshots into the bush/fog of war, placing a ward, using an ability that gives vision. but a damaging Smite, either instantly killing her as her E is casting, or killing her through the stun anyway would shut her down and feel pretty unfair IMO. I still don't think Smite should be castable through stuns regardless. Does anybody know if there was an iteration where it couldnt be used through hard cc? What was wrong with it?