Ok, myself and someone else had a long conversation that had a lot to do with how mob ac works. I did some tests, and found something that doesn't seem right, not to me at least.
When in combat with deep red mobs, there is a definite AC reduction to the damage you are doing. My level 20 fixer fighting a nano architect that was deep red to me in a level 35 mission using a ql16 micheal patriot and various self buffs, out of about 75 hits, his highest damage hit without a critical was 33. Using the same buffs etc, when fighting a dead even yellow human mob in a 50% mission, his highest hit without a critical was 47. Using the same buffs etc, when fighting any grey human mob, his highest hit without a critical was 47. So according to this small series of tests, a yellow mob's ac was no better than a greys. I could run around one of the backyards all day at level 20, and never do more than 47 damage on a non critical hit to leets and reets. But fighting red mobs there is a damage reduction from ac.
So this tells me that any mob you con yellow/green/grey to (excepting the weird advent/soldier mob thing), effectively has 0 ac. How can this be right? It totally removes the purpose of using a weapon with different damage types like fire or radiation, or weapons with a high minimum damage but low maximum damage for good armor penetration against anything yellow or lower.
Here is another situation, my level 65 fixer with a ql75 nova flow vs giant cryptthorns in clon**** that are yellowish/greenish to him. If I remember correctly, a ql75 nova flow does about 1-120 base without criticals. With hasty augmentation cloud, a +5 energy ring and a +2 energy ring, and about 310 attack rating, he could do around 210-220 max damage to giant cryptthorns. Thats about 100 damage over the base damage of the nova flow. I don't know any formulas for converting attack rating into extra damage, but it sure seems like he is getting the FULL bonus from it vs a mob that is just a teeny bit lower than him, which again seems to point toward the mob having 0 ac or an ac that is effectively 0 for whatever reason.
Is this the way it is supposed to be? The only time you want to use a weapon with fire damage or high minimum damage is when you are up against deep red mobs where there is an actual damage reduction? Granted, mob difficulty is pretty tough as it is right now and I DON'T want to see it made harder by changing the way things appear to work right now. But maybe you need to look into this for when/if you consider doing the overequipping changes and parallel mob difficulty changes.
Before anyone tells me i'm wrong, go out and do some tests yourself. If you find that you think i'm wrong, tell me exactly what you did so I can duplicate it to see for myself. So how about it Funcom? Is this the way it is supposed to work? Maybe you could give us an article on why mob ac seems to drop to 0 when you are equal in level to it.