Let's break down how armor works now, since quite a few things have changed. The basic idea is that armor reduces physical damage from hits and works better against smaller hits than big ones. Your reduction is based on your armor value compared to the incoming damage which means having 10,000 armor will cut a 1,000 damage hit in half, pretty straightforward.

The really interesting part is the new armor break system that's been added. When you hit enemies they can get their armor broken down over time, and once they're fully broken several skills get powerful bonuses. Sunder gets guaranteed crits while leap slam builds up stun way faster, so it's worth building around these effects if you're going for a physical damage build.

There's some cool ways to make armor more versatile now too. The heatproofing passive lets your armor work against fire damage, and iron reflexes can convert all your evasion into more armor if that's your thing. Some unique items like brass dome got buffed to give way more armor with fewer downsides, making them actually worth using.

One thing to keep in mind is that armor still needs other defenses to work well, even after getting buffed by 15% recently. It's best paired with other defensive layers but focusing on armor breaking enemies while stacking your own armor through things like hulking form and good gear can make for some really solid builds these days.