Devastate threat values 

From wow.incgamers.com

Author: Lavine, http://beta.worldofwarcraft.com/thread.html?topicId=1101439&sid=2

With the Devastate (rank 2) damage formula up, the only thing left to figure out was the threat. With the help of Lousyanneg aka ILT@Shadowmoon-EU the orc bashing began once more.

- First we confirmed the 110% threat required to transfer melee aggro.
- We also confirmed defensive stance without defiance still generates 130% threat compared to a priest 100%
- We confirmed the Sunder Armor rank 5 threat value to be around 261 as previously published at http://www.wowwiki.com/Formulas:Aggro

Then began the testing with Devastate. With the regular threat meter addons being unavailable for beta, we had to do things manually with a damagemeter and a calculator.

Method for the experiment was as follows: Warrior begins to beat up the target with Sunder/Devastate, depending on which was researched. When the chosen number is applied, warrior stops and priest begins to beat up. Experiment ends at turnover point.

Factors taken into account for making conclusions:
1) White warrior damage
2 Devastate warrior damage
2) Priest damage at turnover (all white)
3) Number of Sunder Armor applied (1 to 5)
4) Number of Devastate applied (always 1)

We recognise the random factor that was involved in using a level 3 mace and minimum damage by attack power. However, the initial purpose of this experiment is not to find out threat values up to three decimals behind the comma, but rather to find out roughly what Devastate does to us. All things that could possibly generate threat were removed from the talent trees/unequipped.

Additional Devastate threat = Priest dam. / 1.1 / 1.3 - ( 261 * Sunder Armor + white warrior dam. + Devastate dam.)

To our surprise, the missing threat was always around 50 with one Devastate applied, regardless of the number of Sunders on the target. We can conclude that, opposed to what the Devastate description suggests, innate Devaste threat is a constant 50

However, lets not forget about threat caused by the increased damage part of Devastate with multiple Sunders applied. The damge formula:

0,5 * ( Weapon Damage + Attack Power / 14 * Normalized Weapon Speed ) + 25 * #(Sunder Armor)
(see Devastate damage formula)

... makes sure that around 25 threat is added for each Sunder Armor applied on the target in addition to threat caused by 50% weapon damage

A tier 0.75-ish (yeah I know it doesnt exist :p) equipped protection warrior with Quel'Serrar like myself deals 100 damage with Devastate, which is 150 base threat, compared to 261 Sunder Armor rank 5
With five Sunders on the target, that's about 210 damage (armor reduction ftl), thus 260 base threat, equal to Sunder Armor.

Whether or not this is good or bad, I suppose everyone feels differently. Myself I won't be using Devastate to tank with unless the target has already five Sunders on it. I'll keep using it to solo stuff though, it's a good buff to the protection tree for that purpose, have to admit that.

I do have my doubts about the use of warrior tanks at level 65-ish, with Sunder Armor rank 6 being available at 67 and Devastate not providing a real solution. Everyone's dps scales like mad with the BC gear, and Sunder Armor rank 5 is going to be stuck at 261 threat. Druids will overpower us with Maul for sure at those levels, as it scales with gear (and they get a new Maul one level before we get our Sunder armor.) I'd support a Sunder Armor rank 5.5 at level 62.