an alternative title would be: "human=8.5% more aggro in tanking" or,"why you are screwed if you are non-human"
I have been long puzzled by the huge miss when tanking raid bosses, my typical combat log parsing would show 9% miss, 15% parry and 6% dodge against boss, which makes up a whopping 30% total miss against boss.
A recent study on elitistjerks has shed some light on this:
http://elitistjerks.com/472075-post527.html
before I get to the results, let us go over what weapon skill usually do when you fight mobs below your level. attacker's weapon skill works against defender's defensive skill, you take the difference between them, and every 1 point of difference will give you 0.04% less miss, 0.04% less dodge, parry, crit, etc. so when you fight mob 1 level below you, you will have 0.04%*5=0.2% less miss,dodge,parry, 0.2% more crit. etc.
However, blizzard introduced a much bigger penalty when you fight raid bosses. Raid boss is consider level 73, and the normal difference between boss defense and your weapon skill is 15. The following table shows the penalty for every point of difference.
Stat Base >10 <=10 +10
Miss 5(24) 0.4 0.1 1
Dodge 5 0.1 ? ?
Parry 5 0.6 ? ?
CritPen 0 0.2 ? ?
1） the penalty is big, it is roughly 10 times higher than then bonus when you fight lower level mobs. the penaly is nonlinear, it is much severe for the first 5 points than later ones, first 4 point of weapon skill equal .4% hit, the 5th weapon skill point equal 1.4% hit. later weapon skill point equal .1%hit.
another way of look at this is following table
Target 3 levels higher, one-hand or two handed weapon or ranged, no +Hit through talents
Skill Hit Miss Total Decrease
+ 0 141.92 9.0% + 4.0% 0.0%
+ 1 135.62 8.6% + 3.6% 0.4%
+ 2 129.31 8.2% + 3.2% 0.4%
+ 3 123 7.8% + 2.8% 0.4%
+ 4 116.69 7.4% + 2.4% 0.4%
+ 5 94.62 6.0% + 1.0% 1.4% --> 1% jump
+ 6 93.04 5.9% + 0.9% 0.1%
+ 7 91.46 5.8% + 0.8% 0.1%
+ 8 89.89 5.7% + 0.7% 0.1%
+ 9 88.31 5.6% + 0.6% 0.1%
+10 86.73 5.5% + 0.5% 0.1%
+11 85.15 5.4% + 0.4% 0.1%
+12 83.58 5.3% + 0.3% 0.1%
+13 82 5.2% + 0.2% 0.1%
+14 80.42 5.1% + 0.1% 0.1%
+15 73.85 5.0% + 0.0% 0.1%
2) The penalty applys to both dpsing and tanking, but for tanking it is more severe cause the parry penalty is huge. and for parry, some part of the table is not figured out, it is not clear if it has the 1% jump at 5th skill point.
3) First 5 point of weapons skill is important, It will give you 3% less miss, 4% less parry ( if there is a 1%jump), 0.5% less dodge, 1% more crit, a total of 8.5% more threat against raid boss. so human warrior will have 8.5% more threat than other warrior when using sword, mace.
4) A good racial should make roughly 1% difference, draenei have 1% hit, nightelf 1% dodge, human 5weapon skill is roughly .8% when fighting lower level mobs. However 5 weapon skill=8.5% fighting raid boss is just too strong racial.
5) It is not the first time blizzard make this kind of mistake, in Wow classic, melee auto attack have 40% chance of glancing blow against boss, but for human it is like 10% because of the weapon skill and boss is considered as level 72 boss for human because of the racial.
6) What blizzard should do: i am perfect ok with blizzard introducing the raid boss hit penalty, but the penalty should depend on level difference not on weapon skill difference, so boss will be considered as level 73 for all of us, not level 72 to human, level 73 for rest of us.
7) What you should do if you are non-human:
There is very little itemization on weapon skill, for the advanced guild, there is glove of enforcement gives +5 weapon skill, mallet of the tides gives +4 weapon skill, not good enough to break the 5th weapon skill magic points. for the rest poor guys, you can get the lower city exalted ring which give 5 dagger skill and use a dagger.
In summary, human 8.5% more aggro ftw! rest of us, not so lucky, thanks to stupid blizzard design.
Edit: A few people kindly pointed to me that it is not clear yet whether weapon skill has impact on parry rate, it is still to be tested. If not, then human would have 4% more aggro not 8%.
