Zileans ultimate should have an activation timer.
It's really unfair and stupid that zilean has this powerful ult that goes off immediately.
WARNING: I am not claiming zileans ult is overpowered. Before people spam this post saying that I'm a "bronze moron being salty" just understand that in no way this is saying the ability is overpowered.
Anyway, it should have an activation timer of about 1 second. This is because he can just use the ultimate right before another ability with an activation timer goes off (examples: lux ult, Syndra ult, obliterator in nexus siege) and survive. Normally, people wouldn't attack him when he has his ultimate up, but when an ability with a cast time is used, they can't cancel it and he can therefore ult himself.
Giving it an activation time (anywhere from 0.8-1.6 seconds) would prevent this.
Also, for an ability that can frikking revive, if it goes off immediately, there's really no counter to it. Other abilities that are considered strong like Cassiopeias ultimate have counterplay- face away. Other examples are bards q, stay away from allies when he's in range, or twisted fates ultimate, which gives you reaction time as you see him slowly appear. Zilean has none of this. If the person could be killed before it completely goes off, there would be counterplay.