Asheras wrote on Feb 22
nd, 2016 at 10:03am:
Agree with your comment on AC. AC is still a valuable component. People want to say AC is pointless if you can't get to 95% like in the old days when it was d20 based. But even if it is only causing misses 35-40% of the time on a light armor build, it is adding value. And you can stack that with Dodge, Blur, Ghostly. It all adds up. Then you need PRR and solid HP for the times you do get hit (because you will get hit sooner or later). Crowd control helps with that too. You have options for CC, even on a dex tempest ranger. You ignore any of it and your build suffers in EE/LE content.
About 6 years ago I got into a huge fight with people about Rage. Sadly what people didn't understand then, and what people still don't understand, is that the game has never used a D20 system. What it does is computes a viable AC range based on the level and difficulty and then breaks it down into what I believe was (and possibly still is) something to the effect of a 25%/50%/75%/100% system. This was a while back when good AC's were like 80-100. So for back then, say you were in Amrath Elite.. the range is always an 8 point system... so in any given dungeon.. for example say Amrath Elite.. the range is 94-102. Anything below 94 you are always going to get hit, 95-96 you will get hit 75% of the time, 97-98, 50% of the time, and so on. If you had back then a 102 or over AC it probably capped at like getting hit 25% of the time.
Today, with possible AC around double what it was I am guessing it has been expanded to probably a 16 point system. But this is why I always tried to explain to people how Rage was a bad thing because if your AC was within range, it lowered you an entire tier (i.e. getting hit 50% to 75%).
Gullible as people are they of course think that monsters are actually rolling dice for every swing adding a bonus and measuring that against a character's AC.
Willing to bet dollars to donuts that they have probably taken that system (most likely on a 16 point range now) and then composited it with blur /ghostly, dodge etc. So as you say, ditching AC or even simply being far enough "out of range" for whatever it should be for that difficulty, most likely tanks your chance to defend.