Let’s take Conqueror against everything. Even if there are no tanks in the game, let’s still take Conqueror.
Oh you built Ninja Tabi and Thornmail to counter Trynda or Jax, it doesn’t matter because Conqueror will make that armor useless.
Oh you build Zhonya’s to try and counter Zed, Conqueror will make that armor useless.
Let’s take Conqueror and destroy tanks at all stages of the game. Let’s take Conqueror and overkill squishy champions.
Full tanks cannot tank anymore. Squishy champs that build one armor item still die just as quick while making the armor item useless.
Other keystones average around 1000 damage all game and these keystones are adaptive damage and have cooldowns. Conqueror can achieve more than 7000 damage all game with no downtime and it deals true damage. But what gets nerfed? The other keystones. Conqueror only had a -4AD nerf at level 1.