Please change the Accuracy stat...

[Hioki]

Let's not remove it. It's nice and simple, and gives players something to budget their secondary stats around.

That's exactly why accuracy is a terrible stat. You should never have to budget yourself around a stat. Instead the stat should become less optimal than other stats but not a burden if you have more than you need. The current issue is: If you have too much you just wasted a better slot for secondaries, if you have to little you need to find more and will likely cause yourself in an overage. When a stat negatively impacts you for having it, it's bad design.

It's really complicated and I can't tell the difference between glancing blows and Block/parry.

Also, I'm not sure how Arpen works with CDs that increase the amount of defense and armor players have (e.g. foresight).

Block and parry are defensive stats that occur due to incoming damage. A glancing blow occurs on outgoing damage. A glancing blow would be largely irrelevant for dps as it's likely you would meet the acc anyways. However, Arpen is the offset for having too much accuracy so you're never hurt due to bad itemization or bad rng. Conceptually, you would not be able to gain arpen through any other method except accuracy. This would also help with healer damage/debuffs as they would never miss even under the cap, they just wouldn't do the full damage. Which is still better than doing no damage at all.

Arpen would work how they want it to work. You can stick it on the end or towards the beginning of a calculation with varying effects.