Give natural sustain to an ad carry is broken right now, the life steal is just too strong, an ad carry can be full health in few hits, even a small heal in top of that, and the escape mechanics, plus the mobility than his build TF give him is way just too strong right now.
The same with the slow, they are nerfing the phage/TF exactly because it was too strong of how corki and Ez can poke from 1k range with slow procs, giving it in his W that has already large range is eliminating any change run, you will have to engage him every time
I want to think at least Ez will be picked for specific comps, like a poke comp, or with certain supports, not with almost everything.
Point is, he needs something to compensate. One 1k range spammable skill does not justify taking away a big portion of his kit.