Exhausted is BRoken!

No, I don't agree. Exhaust is a summoner spell, on a cooldown higher than most ultimates, that doesn't even stun someone. It slows down their movespeed and attack speed. It doesn't do damage, it doesn't stun, it doesn't stop any abilities, and taking it means that another spell, such as Flash, Ignite, Heal, etc., can't be taken.

Mind explaining how Exhaust is broken?

When used right? Hell yeah it's stupidly broken.

Glad someone noticed how effective it really is :)