Jayce's statistics show that his early game is the majority of why he's unbalanced.

First of, let me say that his play-rate and win-rate between 6.19 and 6.20 are almost parallel in their proportional increases. That's extremely unnatural for any champion one may claim to be 'balanced', especially with a massive influx of players like Jayce is experiencing.

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Take a look at is his 0-25 minute win-rate. He sports a massive ~57.4% winrate before the 25 minute mark. This, along with the massive drop-off of almost 10% past 35 minutes shows he's an issue specifically due to his laning.

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Another thing of note is games played.

A player that has never played Jayce before still holds an average of a ~50.5% win-rate. Between 1 and 125, his win-rate is relatively stable at ~%51. This skyrockets to a ~56.7% win-rate past 125 games played.

**~87.5% of players have not played more than 50 games on Jayce, yet he still never dips below 50% average win-rate in any data bracket outside of post-35 minutes. **

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What this data all shows is that Jayce's laning phase specifically is a problem. Its too easy. His early strength is too consistent. He has too many tools and his numbers end up too high too early.

His late-game is comparatively weak, so Riot could possibly nerf his early-mid game and buff his late-game in order to address this problem without upsetting true Jayce mains.

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The final thing to take note of is that Armor Pen is the main reason Jayce's early win-rate is so high. Players started forgoing Tear, instead opting for Armor Pen, making him significantly stronger early on in the game.

With the preseason, Armor Pen itemization is receiving significant changes, and this may stabilize his performance again.

I, personally, believe his early game will still be an issue, since players in general realized that you don't need to go Tear, still providing a significant improvement to his early game.

However, keep those Armor Pen changes in mind and stop asking for nerfs until after we see how the new itemization affects him. Riot has already stated there will not be much champion-specific patch content until after Pre-Season is set in stone, with the exception of those that are already receiving significant changes.

Asking for Jayce nerfs before the new itemization comes in is essentially a waste of breath, if what Riot has said is true.

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Source: http://champion.gg/champion/Jayce ---- 6.20 patch data.