Sweet build, I run acid spray on my stam sorc today for aoe instead of steel tornado also, with endless hail/acid spray and hurricane its fairly easy to stay well above 50K dps in quite long garbage pulls.
I was able to run trap on my back bar instead of acid spray, and had steel tornado on my front bar. This is a fine option for AoE and many of you will be comfortable doing so. As @AlphaRahl pointed out, but the above set up provides us with an additional Fighter's Guild ability on our main bar, increasing our dps, while also enabling us to stay ranged when dealing with mobs. In case it's not obvious, that is why we have Flawless on our front bar -you will basically never use this, but it's there for the passive damage growth -constantly continue to generate ultimate till you can pop Standard, unless it is at the end of a fight or you're desperate for resources.
Head & Shoulders -Kra'gh. This new set is best in slot and a . The one piece penetration bonus is the best thing for Stam builds going, and your dps will be boosted by the 2 bit set well. Run Velidreth instead, if you don't have these 2 bits however. Another fun option is to run an additional 2 pieces of VO here. While this won't optimize your dps, it can be fun to perform for farming runs where you aren't too worried about time, as the rate bonus and increased resources are terrific.
Your flex spot will be dictated by your group needs and the situation. As a DK, be prepared to run chains to your group. As a stam user, you may be expected to run rapids if your group is going for aggressive raid scores. If you don't need to run, slotting Vigor is a excellent option. Blade Cloak is also great for damage mitigation, especially in vSO. Caltrops is a worthwhile skill to run on your back bar if you have the space as it will net you about a 1k dps growth; however, be aware that different morphs of caltrops don't stack against single target. I run Anti-Calvary Caltrops since I also run 5 part NM, so I have an opportunity to proc the debuff on multiple enemies.
Other 5 Pieces -this will vary depending on your situation. For my trials team, I run Night Mother's -you always need one person running this set on your squad for the 5 bit penetration bonus. If someone in your raid is currently using NM, then you can use TBS instead . The dps difference between NM and TBS is minimal, however, TBS is nice in that you get a health bonus of about 1k. Notice: TBS wins out at an optimal raid setting where warhorn is always on cooldown. If you're not in an optimized raiding team, or if you are just doing a dungeon, using NM is fine.
For trash and AoE scenarios, simply maintain Trap and Hail while light attack weaving Acid Spray. For fights where you want additional ranged damage, feel free to slot Snipe. Focused Aim is probably the morph you want since it will give your group Minor Breach; if you've got a Stamplar in your team or if someone else is currently running Focused Aim, then you certainly want Lethal Arrow.
Intro: Sadly, the meta has shifted to where having the majority of a raid's composition is mag DPS. However, if you still insist on bravely running a stam DK, I have you covered! With no Maelstrom weapons and subpar CP allocation/gear you will be able to break 20k DPS easily, and with an optimal set up and clean rotation you will be able to pull 30k -40k+ single target. Please note that this guide is intended to help you with dungeons and trials only and is not intended for vMA or other play.