@Riotrepertoir nerfing Fizz's E is a mistake

I know this isn't official and this may get downvoted because I said that we shouldn't nerf the troll poll but bear with me. This is the quote this is about:

Honestly, it probably doesn't make sense to stay what it is if tanky builds are effective for him. Having burst avoidance/mitigation is cool, but having it on top of general tankiness, good damage, and mobility probably isn't cool. I'm not sure whether the best thing to do is to nerf Fizz's E, or to just make him do less damage with tanky builds.

Normally this wouldn't worry me but it does now because I saw another post about how fizz may get changes in 5.17/5.18 and I want to explain why nerfing his E is a bad idea. So Fizz's intended build is as an AP assassin but has recently been built as a bruiser/tank and received a lot of hate for it because he retains his slipperyness and some of the burst while gaining tons of shred and damage from his W while being tanky at the same time as well as still getting the 20% damage increase on his ult. So it seems the problem is his itemization. Problem solved. However, what part of his kit allows him to build those items? His W is one option and Riot tried to fix that in 5.7 and it gave AP fizz a substantial buff but it didn't really nerf AD fizz at all. So it must be something else. Here's my suggestion, make the 20% damage increase on his ult, MAGIC damage only and not ALL damage. This way AD fizz will be missing a huge part of his kit, punishing AD fizz but not hurting AP fizz. This is a better option because nerfing his E is only a nerf to AP fizz and doesn't do anything to AD fizz, the problem.