Life Steal, and Draven.
I've seen this multiple times, a Draven walks into the enemy team, or gets caught out and they just lifesteal (Deathsdance) all the incoming damage and is able to survive up to 3 even 4 people at once. I think it is a big issue that needs to be looked at.
Now that most assassin burst is delayed and adcs have time to "counterplay" they can life steal in between the bursts and survive longer. Maybe its just me, but it doesnt feel healthy to me.
Thank you for your time!