So how do we feel about Thornmail?
Thornmail seems to be a very divisive item to me. Most either say it shouldn't exist (I'm one of them) or they say that its a kind of necessary evil to stop the ADC menace.
I think its counter-intuitive to have an item in the game that directly punishes you for attacking. Randuin's slow is one thing, because it can be overcome and its up to the enemy to make use of your slowed movement, but Thornmail is the only item in the game that makes it so enemies can quite literally kill themselves.
as a 4th or 5th item. Thornmail is on the cheaper side, but I personally think it should cost more in exchange for the buff above. I'm pretty tired of going tanks and fighters with 300-400 armor and getting shredded by ADC's like Draven, Vayne, and Cait while they actually manage to lifesteal over it, which is silly considering the stats. 30% damage reflection before magic resist. Many ADC's except Vayne get 20% Lifesteal, thus they should be taking at least 10% damage before resist. Last Whisper in its current iteration seems to bypass this making most tanks without a direct leap absolutely useless in the lategame. When I play or someone else plays a tank. I expect them to get kited and die. But when many of them die before they can cc, there's a problem with the way the items work.