@Riot, Heimer is ill and needs your love
First look here: http://champion.gg/champion/Heimerdinger/
Toplane winrate: 48.66% Midlane winrate: 48.72%
That means even hardcore Heimerdinger's mains can't win with him! Some may say: this is how he's balanced. But Riot said Heimerdinger is balanced when he has winrate >50%, because he's not so popular, and unpopular champions usually have higher than average winrate because only hardcore mains are playing them. Riot words here: http://euw.leagueoflegends.com/en/news/game-updates/gameplay/data-and-champion-balance-part-1 (50% doesn’t mean balanced).
Why Heimerdinger in so bad state? What changed?
**S5 toplane ** His problems started in S5. When Rivens and Irelias became very popular, it was start of the end. Riven has AOE (for clearing Heimer turrets), CC (for catching Heimer), shield (for surviving his burst), mobility (for dodging his grenade). Irelia could Q on Heimer's turret and catch him - so it was self-countering from Heimer. Plus sustain and AOE from ult. However this matchup was easier than vs Riven.
Then Juggernauts came. What changed? Before update all those champions (Garen, Darius, Skarner, Fiora) had to choose: to be tanky or to be offensive. And it was ok for Heimer: glass cannon Dari could oneshot him, but he could oneshot Dari too. If Dari was tanky, then Heimerdinger has nothing to do with Darius and had to simply ignore him. Same with Fiora. But after update, Heimerdinger was able only to lose - tanky and same time with tons of damage. Should I tell about Darius sustain and CC that he never had before? Or Fiora with her counterspell for any counterplay? Heimerdinger stun has long animation, and player of any level can counter it with Fiora's Riposte.
GP update was just killer to Heimer. Tons of AOE, rip Heimer's turrets.
S5 midlane Riots made Azir. What Heimer could do to Azir? Azir is an upgraded version of Heimerdinger: longer ranges, shield, mobility, untargetable solders, own tower etc.
S5 items What was happening on midlane same time? Luden's Echo. Heimerdinger always vulnerable to AOE, and Luden's was super cool way to clear his turrets with one shot. Nuff said.
AD champions get Sterak's Gage. If someone didn't know how to beat Heimer on toplane, there is simple recipe: Hexdrinker. You jump on Heimer, he stuns you with grenade, uses his burst (uber tower or rockets) and presses Zhonia, his turrets hit you with beats. And there is your shield poping up. Heimer is standing still in Zhonia, you're clearing his turrets and killing him when he's out of stasis. Gg. What Sterak changed? EVEN MORE SHIELDS to counter Heimerdinger.
More AOE for AD champions: Titanic Hydra and Statikk Shiv.
Dead Man's Plate gave same time mobility, tankiness and cc - great options to catch slow and quishy Heimerdinger.
S6 overall In 6th season champions get even more AOE items: Rapid Firecannon, Guinsoo's Rageblade. Many items, that were counter to Heimer already, were buffed: Maw of Malmortius, Iceborn Gauntlet, Runaan's Hurricane.
In mage update Heimer's #1 item - Zhonia were nerfed.
Result Now we have sad numbers: toplane winrate: 48.66%, midlane winrate: 48.72%. Please, even if Heimerding is not popular like Zed or Ahri, he still has it fans. Don't forget about him!
And please do not downvote this post without writing why are you doing it. It took time for me to write it.