So I am in a campaign, post apocalyptic, think Mad Max, Fallout, borderlands, Fist of the Northstar, Book of Eli, ect... Where everyone seems to have a high miss chance. I posted another topic about tied rolls, but this one pertains about AC for the whole party.
The DM I think made the AC ridiculously High for everything to make up for the have that two party members rolled high, and after race we had a dex of 20. "Me and the Monk-fighter." So at level 3, Me and the fighter have a +7 to hit. So everything we fight seem to always manage to find cover "one time using the Monk-fighter as cover" at level 3, while flatfooted, had an ac of 24, lovely. 5 random Human thugs and raiders seem to have health well over 20, and ac in the 17s up. I think he boosted the AC because of us, but this took a toll on the other members, one who has a +3-+4 hit chance.
We are using home brew classes from the DM, its basically a D20 modern Campaign, using pathfinder rules. The "spy" is just the pathfinder rogue, with a few "tweaks" he has all of his abilities still but I can replace my rogue talents with "spy gear". A soldier, which gets everything a fighter gets, I think he gets something that makes him better somehow, but I don't recall.
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A tech specialist, I'm not sure what this class is like at all, but he basically can heal and makes robots. "He can heal cyborgs and robots, but not living humans, o joy." He gets robot minions, and a big robot minion that functions like an animal companion. His little robot minions each with an HD of a combine total of twice his level, but none of them can go over his level. They use his base attack. The big one has his own chart, and is actually useful. The little ones are smaller, and can only use melee attacks, they hit for 1d4, and have NEVER IF EVER, HIT ANYTHING. They are most useful for giving everyone a flanking bonus, and a type of Monk-psionic fighter mind blade thing. He basically gets mindblade, full base attack, and a few "chosen" psionic powers.
I mention all this because it seems at the core of all of these problems, was an issue of balance, or lack there of. The DM was fearful of making these classes too powerful that he made them underpowered. The tech specialist is completely useless in combat. This was the intention, but I mean completely useless. His Robot "animal companion" pretty much does everything, but comes off as second rate fighter.
The tech specialist his smaller robots, since they are not allow to use guns, already have a movement of 20 feet, and have never actually hit anything. In theory, this class was a nice idea, in practice, he basically hides in a corner until one of the cyborg characters comes by and needs a "heal". Since they have regeneration, this never happens. Since My character is not a robot/Cyborg, I run away after getting shot. "Probably realistic in that aspect :p." The tech can heal organic people at level 4. So he has a low base attack, since he counts as a "caster".
Even so, a fighter at level 3, with a 15 on their highest stat to be sensible if they didn't roll lucky. Would find a +7 on attacks with feats, to be sensible. Since he is a fighter, he "should" be hitting all the time. I have a +7 without using my two weapon fighting, or rapid shot feats, and i miss with rolls of 16s, I'm usually attacking while hidden too.
I don't use my guns to often, since missing is likely going to happen. "He wants us to feel the weight of lose in this campaign." So I use a sniper rifle that does 2d8 damage, it only had 4 rounds in it. When I finally use the thing, it misses twice. Then again on a "boss" it hits once, even though I was in cover and hidden, he was flatfooted, and I was a good 100 feet away. "it's a sniper rifle, I did not get any negatives." All rolls where above 13. Heck, even the fighter monk in our group misses half of his attacks. He just made sure he does around 20+ damage when he does actually hits with his feats.
This is a good guide from the bestiary as to about what AC should be for a monster at certain CR.