What's with exhaust nerf?

The real nerfs should have been to make Heal and Ignite have 300 second cooldowns but they attack exhaust instead. Total sense, why nerf items used to spam hundreds of health recovery or damage every 3 minutes and change (far less with masteries/Ionian boots) when we can gut exhaust for no good reason?

It was way too strong and universal.

People are dealing so much damage because they can use exhaust and remove 10 armor and magic resist from the target and therefore deal more damage especially if you've got lethality on top of that (the less armor and mr you have the more damage you take).

It was being used as an aggressive combat spell instead of a defensive spell. Blame corki and gangplank