More Perks?

[MrGrendel]

Armor can't be dispelled / it saves some classes a spell slot / people with mage armor in a prohibited school still get 3 or 4+ additional ac out of this / shields also have magical bonuses, so even then it will go beyond "just" 2+ ac, which by itself is already a good bit more advantageous than existing perks that are comparable.

[Drakill Tannan]

If you take the feats, wich is already a sacrfice. Furthermore you underestimate the power of other perks. The elemental perks are pretty good.

[MrGrendel]

"Having to" take a feat is not a sacrifice, you gain the benefits of the feat.
 
If you want a feat to compare to, one without the drawback of spell failure balancing it out, let's look at dodge: 1 ac against one single attacker a round. -5% spell failure for a constant 1 ac is still more than plenty.

[Drakill Tannan]

I meant compare with perks, not feats since this is a perk suggestion, not a feat suggestion. Anyway...

Bestial
More a beast than a man, your phisical abilities and keen sences are beyond most of your race, but your rational thinking and... well any kind of thinking is always lacking.
+5 bonus to listen and spot
Tracking ability
-2 Inteligence.

[Nightshadow]

I like the Bestial idea, but +5 listen/spot is pretty strong, especially if you add in the likelihood of ranger levels with that, which give +4 spot/listen. An additional -2 charisma may balance it out, though.

[Drakill Tannan]

Or even a total of -4 Inteligence, the perk is meant to make a PC more of an animal, less of a person.

[The Crimson Magician]

can i be a majestic lion with this perk?

[Decimate_The_Weak]

Tantrum: (barbarian only)

When you get mad, you stay mad. You unleash all your physical energy on the poor guy that pissed you off... you better have time to catch your breath!

-2 Will during Barbarian Rage,
Barbarian Rage lasts twice as long, but after it expires, the user becomes weaker for the same duration as what he's able to rage.

[Egon the Monkey]

Armor can't be dispelled

Nor can Mage Armor. Anything that adds an item property is undispellable.

it saves some classes a spell slot

There's quite a few +1 spellslot garments with the same effect, and definitely more useful robes than medium armors for a PC that can cast.

If a perk could give -10%, i think it'd be fine. Mithral armor is uncommon yes, but far from impossible for anyone with medium prof to acquire. Removing the relatively low but still annoying spellfailure from leathers would let bards have the light armor casting they're meant to if they take this perk, and be awesome for say, martially-inclined Evokers who could go about with armor. Incidentally, a shield has effectively 0% Spell Failure, as you can unequip to cast, and for a Wizard, Expertise is an amazing choice of feat compared to armor. Just put it up every time you're done casting and it's +5 AC no spellfail, lasts until the next cast ends.

Obligatory relevant Perk suggestions:
Strong Back
"Faith might move mountains, but you can at least move boulders."
+2 Strength
-1 AB and damage
(or any other way of increasing carry weight)

Know-It All
"The walking, talking, condescending image of an abrasive smart-ass. People get sick of your superiority, and fast."
-1 Charisma
+3 Taunt (+2 overall, note CHA loss)
-3 Persuade
+2 UMD (+1 overall, note CHA loss)
+2 Lore

Fast Metabolism
"Toxic substances might go right through you, but wow are you hyperactive."
+4 Will versus addiction
Drugs last half as long.
+1 vs Poison
+10 minutes to Rest timer

[Drakill Tannan]

nvm-

[Drakill Tannan]

Undead Hunter (Rogue only)
You've learned not to trust too much on your "hit-where-it-hurts" skills due to the amount of undead you've found on your journeys. Luckly for you, you know a few tricks to deal with them.
Effect: Through an option in the crafting menu, the rogue can create any number of undroppable/untradable vials of holy water at the cost of 5gp and 2xp. The rogue gains a item that allows her to cast "Disrupt undead" three times a day.

De-Mechanist (Rogue only)
Golems and the like are probably the worse enemies of the rogue. Through study and god knows how many failed bulglary attempts due to some golem guardian, you've learned how to get past them.
Effect: You gain a special ability of unlimited uses/day that deals one damage per level, and slows the golem for 1d3 rounds as long as you succeed in a touch attack.

Master of poisons (Rogue only)
Nothing better than a few drops of poison to deal with a small problem. You know this, so you're rather good at using poison yourself.
Effect: Bonus feat: Use poison, poison weapon lasts 5 rounds instead of 3, through the crafting menu, you can craft 1 random weak venom at the cost of 20gp and 8xp.

Master of the unseen (Rogue only)
Prior training or experience on remaining unseen in plain sight have given you the ability to melt with any enviorment perfectly.
Effect: +8 hide/Move silently while standing still.

Hide amongs the crowd (Rogue only)
Cloaks, crouching and carboard boxes are great for passing by unseen, however, you've learned there is no better way to do so than using crowds to do so.
Effect: +2 hide/move silently for each PC or human/demihuman in a radius once there are 3 or more of these arround.

Make-up master (Rogue only)
The best disguise is the one used all over your skin. You've mastered the ability to paint yourself in such way, you're very dificult to actually see.
Effect: The rogue can create an item with 1 charge of camuflage that cannot be dropped/traded at any time she wishes at the cost of 15gp and 5xp.

[Kinslayer988]

That Studying Fatass
After studying so long, you have become rather anti-social and gained some pounds. Most see you as unsatisfying, and believe your filthy. However you are much smarter and know better than to talk back at them.
(+2 Int, -1 Cha, -1 Dex, also +8 lore and concentration, -3 tumble)

Beat down Thug
You have been known as a beat down thug and not many trust you, however after all your time you have become tougher and stronger than most.
(Bonus Feat: Tougness, +8 discipline, -2 persuade, -4 bluff (they know you always lie), Chaotic Only

[Dr Dragon]

Patrician

-Through gold or service you have obtained the status of Patricianship increasing your status in the Dominion.

Requirement (Must be a patrician)

+2 Persuade, Bluff, and Intimidate Within the Ziggurat

[derfo]

gorilla teeth expert

your knowledge of the dental capacity of large primates knows no bounds. gain a permanent undroppable dagger called 'gorilla fang' that has -2 damage and +1 intimidate

[One_With_Nature]

Basically something similar to "Skeliton in the Closet" perk but in relation to a Rogue:

Each reset recieve one random Trap in your inventory. (Could be chance based like High chance of getting a minor trap(50%), moderate chance of getting a medium trap(40%) and minimal chance of getting a strong trap(10%) and the type of trap it is out to random chance.)