Sion actually needs a fucking nerf
http://www.op.gg/champion/sion/statistics/top
still 55% win rate, still 7+% pick rate
HAS NO MATCHUPS WHERE HE GOES BELOW 50% WIN RATE. Yes, you heard that right, sion's absolute worst matchup statistically is singed, which he has a 50% win rate against...
The 8.3 bugfixes were huge buffs to sion, and while they were needed because all bugs ought to be fixed by virtue of being unintended side effects, it's time to tone down sion's power numerically.
Let's take another site
https://www.leagueofgraphs.com/champions/stats/sion/diamond
lol he's actually even more broken according to this site.
https://lolalytics.com/ranked/worldwide/platinum/plus/champion/Sion/Top/
Still an indomitable beast according to this one.
[zombie-nunu-bummed]

and Second Wind (if you struggle to dodge or desperate for that sustain in lane).
has a ton of counterplay too and that didn't stop him from being nerfed back in season 5.