Tahm Kench is too OP if you build him tank

https://scontent-lga3-1.xx.fbcdn.net/hphotos-xtp1/v/t1.0-9/s720x720/12096599_890278994388947_7373018755775501638_n.jpg?oh=6e1652f13022e1b47f6638d59491d987&oe=56866BC9 https://scontent-lga3-1.xx.fbcdn.net/hphotos-xla1/v/t1.0-9/s720x720/12065650_890278991055614_2448262901096467402_n.jpg?oh=2b19675da35661bf406ccd2833e489ab&oe=56962EF2 so i don't often make posts here, or well anywhere. but i think that League is a mess right now. I'm semi alright with the whole tanks can deal more damage than an adc by getting one item after they are tanky (titanic hydra ahem). but what really annoys me is the fact that Tahm Kench's w is so godsdammed overpowered. at rank 5, it deals 32% (+2% AP) of the enemy's max health as magic damage. i don't care about the rest of his kit, that's all fine. but look at this match. i was the kayle, who was building pure damage and attack speed. tahm was building pure tank (and on the way to titanic), and he still almost did the same amount of damage to champions as i did. maybe i'm just upset that tanks deal damage. but seriously, i feel like this needs a nerf. every other tank that deals true damage at least is under 12% true damage. even Vayne's true damage is capped at 8%, and that's because Riot knows that much more would be broken. Irelia's true damage is capped at 75, not even a percentage. Tahm Kench needs a lot less damage for a tank.