Solo lane tahm kench outdamages and outsustains every single champion in the entire game
There's no counterplay whatsoever. He builds pure tank items while dealing so absurdly high base damage only a full build Master Yi or Olaf can even hope to deal damage to him and live to tell the tale. No champions can deal with him early-mid game, whether melee, ranged or mage. His mana costs and cooldowns are both so low he can spam his spells forever in lane, his passive stacks last so long he can afford to miss without them falling off and his Q slows for such a long duration one hit equals a kill in lane. Turrets are completely useless against him - he can afford to tank multiple hits even at the very start of the game because his devour deals so much damage his opponent will die before he does anyway.
How is this fine? Even champions like Fiora, Illaoi and Vayne can't lane against him!
His only counterplay is "gang up against him and flash away when he gets 3 stacks on you". You can't push him to turret because he has no trouble tanking minion waves and if you leave turret range and get hit by a single Q you're dead. There's no lane interaction at all - you're lucky if he lets you stay within exp range of dying minions, even more so if you have a spell with such a long range you can toss it at them from time to time. Seriously, there are NO CHAMPIONS IN THE GAME that can lane against him! Why is he allowed to remain like this? Even supposedly natural counters like Cho'gath, Darius and Urgot can't even farm in lane against him.
Why does he have to be like this when in a solo lane, yet utterly useless as a support? Isn't that what he is intended to be? And if the goal is changing him into a top lane lane bully, can he actually have some changes made to enable lane interaction? He's bullying lane opponents out from the very start of the game - literally level 1.
