This is an outdated post, to check out the new data on highest threat skills for warrior in 4.0, click here.
I've been trying to evaluate how much damage reduction Demoralizing Shout/Roar provides for some time now. Turns out, it's not as easy as it seems. I usually prefer to test things in actual combat instead of using various simulation programs. Not that I actually think that the one result is of higher quality than the other, but simply because it's more fun. I've tried weapon enchants this way, and different gear pieces and skills. Demoralizing Shout/Roar on the other hand proved to be a little trickier.
First of all, the problem about Demoralizing Shout/Roar is that damage reduction is affected by so many other things which you'd have to take into account somehow. I realized it would be impossible for me to test DS in an instance because of the different factors that would interfer. Things like absorbtion shields. The biggest issue about trying it in an instance is simply that nearly everything in heroics nowadays dies too fast for me to be able to first watch how much the mobs hit me for without DS, then apply DS and watch how much they hit me for afterwards. We're talking at least 15 seconds worth of fighting if you want any kind of datas. Even ore preferably since I'll probably dodge a big portion of the incoming hits making it impossible to determine anything about any damage reduction.
The alternative was of course to do it under slightly more controlled circumstances. Alone against some mob that would live for a while so that I could collect some data. I asked Love to help me by healing me while I would simply stand against a mob and watch what DS did to incoming damage. First we had to find a mob which wouldn't be too difficult. I chose the tree-thingy mobs in Crystalsong Forest. But after some tries I noticed another problem. The difference between no-DS dmg and DS dmg wasn't huge enough to make it easy to spot a difference. One would have to collect an average really and that would take some time. Time me and Love haven't had the last few weeks. So I've put this project somewhat on the shelf for the moment. Not entirely though, because I decided to check the allmighty internets for some answers meanwhile.
It seems most of the things said about the effectiviness of DS is quite old. From around 2008 or so. As far as I know there hasn't been any major changes to Ds since then however which means that information is still probably quite correct. Apparently the overall damage reduction from DS is about 10-15% depending on what kind of mob one is fighting. The discussions on the internet generally concern not whether DS is worth using or not. There is no doubt that DS is worth using considering that it only costs one gcd every 30 seconds. Even if the overall damage reduction (physical of course, but that's pretty obvious) would be much lower it'd still be worth using DS.
The discussions are rather about whether it is worth to spec into Improved Demoralizing Shout in the Fury tree as prot, or not. In wotlk warlocks got a change to Curse of Weakness which made it better than the non-improved DS. There are also some hunter pets that have a better atkpwr reduction than DS. Although no hunters use Screeching pets in raids, there is often someone else who can provide this debuff. Considering Imp Ds costs no less than 5 tp it's not really worth it. You can only get a mob to 0 anyway and DS will do that well enough. And in any case it matters someone else will do it better anyway.
So I haven't found much to say about DS unfortunately. while rummaging around on forums and whatnot to find out more about it I did stumble upon something else quite interesting and not entirely in the wrong topic either. This is something I've been looking for myself - a simple list on threat values for different warrior skills. Unlike the other tank classes, warrior tanking is alot about prioritizing and using procs the best way. Paladins tank on rotation, dks too depending on spec (and using Rune Strike procs) and druids only have like two skills they use regularly.
Devastate 1 - 1042
Devastate 2 - 1253
Devastate 3 - 1475
Devastate 4 - 1711
Devastate 5+ - 1961
Sunder Armour - 975
Revenge - 4522
Shield Slam - 7242
Conc. Blow - 3385
Shockwave - 3164
Auto attack - 882
Heroic Strike - 2599
Thunderclap - 2605
Heroic Throw - 3417
Damage Shield - 542
All the creds goes to the creator, someone over at EJ, I did not collect these numbers (unfortunately I don't remember the name, but googling around on Demoralizing Shout should make it turn up). I took this from Tankspot however and the guy there had taken it from some guy over at EJ. It should be noted that these values too are a couple of years old by now. Some changes have been made primarily to shield block which affects Shield Slam, our best threat skill. I still think these values are fairly accurate, mostly because it makes sense when tanking. Also take into account that these exact threat values apply to the stats that warrior had who collected them. What we can see from this is mainly which skills have higher threat values, less focus should be put into the exact figures as they won't fit with your char.
What can we make out from these values? When I tank, Devastate actually plays a minor role in my skill usage. Unlike BC when it was one of the most important threat skills warriors had, it's nowadays used mainly as a filler and to proc Sword and Board. In raids one would want the Sunder Armor debuff up too, but ten seconds sooner or later doesn't matter much. As it is now I use Revenge as soon as it is up and then Shield Slam. Shield Slam has the biggest threat value by far, but Revenge hits several targets nowadays. On raid bosses Shield Slam I use them the other way around with Shield Slam prioritized over Revenge. News to me was how much threat Conc Blow does. I thought one mainly used it for the stun component, but looking at its threat values one can see that it is as good an opener as any other skill. It is funny to see also that thunder clap has a higher threat value than devastate, even after five applications. Yet again one shouldn't underestimate the tanking potential in thunder clap. I usually use it as my very first skill because it has a longer range than melee swings (if I start out without rage I begin with taunt though).
Spamming Devastate is mainly to get Sword and Board to proc. This means skill prioroty on a boss should be;
- Keep Thunder Clap up (unless some other class already has that debuff up)
- Keep Demo Shout up (Same as above)
- Use Shield Block (before using Shield Slam preferably, perfect opener)
- Shield Slam
- Devastate until SS or Rev procs.
- Keep Heroic Strike active (since it uses its own gcd it can be used while using other skills)
Nothing new there really, but it's still fun to see some more specific numbers (as exact as they can be after a couple of years ^^).