Let's talk about stats and weapon ratios

[sox7d]

People keep saying "AC is broken" can someone ELI5 this? Half of people say that it's the best stat, others say it's worthless after like +50 or some shit.

How much of a difference does ATK make? Does anyone have any good evidence or DPS parsing concerning this?

Weapon ratio rating seem a bit fucked to me. On the wiki, they are ranked by their ratio, implying that 1 dmg = 1 dly. However, Wurmslayer (0.62) is technically as powerful as Swiftwind (0.62). Meanwhile, Swiftblade of Zek (11/18) only has two more damage than Jade Mace (9/18). I feel like I'm taking crazy pills.