One shotting is fine
As long as :
- It's not some disgusting mix of uncounterable true damage/%health
- It has a high window of cooldown
- It puts the "oneshotter" in danger by burning his escape
I really don't care if assassins oneshot squishies that have no resistances or health in a millisecond, as long as defense serves a purpose [and they would survive with some defensive items and have the edge] , cooldowns aren't ridiculously low, and tankiness items aren't shit compared to offensive choices.
Oh and even though I think that, I think people should not confuse "buffing tankiness/tanky items" and "buffing tanks". Tanks with high base damage, low CD crowd control are also cancerous unhealthy if defense is good. If Riot wants to bandaid fix the situation by buffing tanks crowd control or base damage, they're beyond retarded.
