Why didn't they rework Zed further?
Zed as a champion is extremely unhealthy. Based on champion.gg he is banned in 37.6% of games, yet picked in only 7.3% of games. His win rate is also low, at 47.9%. This is the 4th highest ban rate, yet the 18th highest pick rate. Lets compare this to fizz, who on some levels is similar to zed. He has an ult that marks you and deals more when he hits a marked target. He is melee and slippery with his e which can allow for somewhat similar escapes and engages to zed w. Fizz has a better win rate and lower ban rate.
The way I interpret this is that people hate him so much that they ban him, even though he isn't picked much and doesn't even win as much. I think the reason is pretty clear, it's so stupid to play against him in lane that it is worth a ban for mid laners even if someone truly overpowered is left unbanned. Additionally I assume a lot of bot laners ban him because his ult is horrifying. The change to his bonus AD will make this worse as no stacking AD player in their right mind wants a zed to camp them and snowball off of them. It will make that game hell for them.
With basically only his bonus AD touched, his lane will be identical to how it is now. Which is horseshit gameplay and really should be looked at. It's just not fun, which is really the core of the problem for me. I don't like playing against his obnoxious free poke, nor do I like to be killed under tower from 70% hp. Let me be very clear that these things are not overpowered as shown very clearly by his win rate. Lots of other champions have poke and the ability to kill you under tower, it's just for some reason which designers need to find out and address, Zed is the least fun to play against of them all.