I still can´t fathom why,
Riot decided to rework Xerath due to gameplay issues, but lets Fizz run rampant!
Sure Fizz got changed a lot too, but the same problems always remained:
- At the beginning the AP burst was just too much (+the E CD/DMG combo).
- Then they made his W more potent, bringing to live AD Tank Fizz jgl.
- They nerfed that and put the focus back on AP, with the addition of the mini DFG on his ult.
- And now with tank items and sustain being almost too strong again, look who´s dominating top/jgl/mid again?
All the while Xerath never went through the process of making him work! They just saw Xer and decided: "Well lets fu this guys kit and playerbase! Why even bother making it work?**".
Can anyone tell my, why are there champions whose kits need to be somehow balanceable (like Riven/Zed/Rengar), while there were champions like Xerath who simply got changed WITHOUT ANY ATTEMPT TO MAKE HIM WORK BEFORE.
Take that plus the amount of reworks that failed the mark pretty badly or were simply unnecessary: 
.
/rant