Hopefully my last post of the day.
In my guild's forums the other day, I struck up a conversation about optimal DPS rotations.
My current DPS rotation, starting from the moment I enter combat, is this:
Vampiric Touch - Shadow Word: Pain - Devouring Plague - Mind Flay - Mind Blast
I'm aware this is flawed -- bear with me. The late Mind Blast is a holdover from my BC days. I have the habit of DoTing up the target (beginning with VT) before casting a MB in order to get mana regen flowing as fast and furious as possible. Mind Blast used to restore the most mana of any of my spells so I wanted to ensure I had Shadow Weaving stacked to max before casting for the biggest damage. These days, it's still the mana restorer, but with an entirely different role in your rotation.
Shadow Priests have gone from a primary purpose of restoring mana to a dps-centric design. My thought process and habits are still in the last era, and I'm working on changing my thinking away from "I am here to restore mana" to "I am here to melt faces." Waiting to Mind Blast till you've stacked Shadow Weaving to 5 is a waste of mana and potential DPS. Mind Blast is the most important dps ability in a shadow priest's arsenal, and any player concerned with maximizing his or her potential DPS is going to want to center their rotation around it.
Take my current spec as an example of fail. I only have 1 point in Improved Mind Blast. The other shadow priest in our raids who, besides being much better geared, does far more dps than I do does so because of Mind Blast, primarily. That is, doing more of them. According to a recent WWS report on Patchwerk, he cast in the neighborhood of 165 Mind Blasts and averaged about 5100 DPS. I did about 3600 DPS and cast 106 Mind Blasts -- only about 66% as many as he did. While gear explains that DPS gap somewhat, the difference in our rotations explains much more, with a sprinkling of interesting ability mechanics. Here it is paraphrased from his words.
This other priest leads off with Mind Flay. Mind Flay has an interesting bug these days that causes it to stack two Shadow Weaving buffs instead of one. I've only confirmed this happening when I have no existing Shadow Weaving buffs, but it may well occur no matter how many you have when you cast it. This is a good thing, however, letting that Mind Flay run its full duration when you could use that time to cast higher damage spells or DoT up the target is probably not such a good idea. "Clip" it immediately -- that is, cast it and immediately start the next spell as soon as the Global Cooldown allows. There is a secondary benefit to an initial Mind Flay, and that is giving tanks time to "threat up," for which 2.5 seconds is, for better or for worse, plenty of time these days.
After the initial MF, the next step is to "start the clock" on your rotation by casting Mind Blast. If you are centering your rotation around Mind Blast, you will want to use it every time the cooldown is up. This is top priority. The rest of the time you will spend keeping DoTs up and Mind Flay-ing when possible. Fully talented, you will have a 5.5 second cooldown on MB, giving you 3 or 4 GCDs, depending on haste, to do other stuff.
Therefore, incorporating this knowledge into a new rotation would look like this:
Mind Flay - Mind Blast - Vampiric Touch - Shadow Word: Pain - Devouring Plague - Mind Blast
There is another little tidbit everyone should know concerning Shadow Word: Pain. When you apply SWP to the target, its base damage is set from any debuffs on the target. When Mind Flay refreshes SWP on the target via Pain and Suffering, the base damage is not recalculated! Therefore, you might think the key to maximizing DPS means you need to cast SWP twice, once at the beginning and once to reset its base damage value once the rest of the raid unloads on the target. This would be a good guess, but to avoid wasting a GCD doing that, we should instead swap the positions of SWP and DP in our rotation in order to give the raid more time to apply maximum debuffs to the target before casting SWP. The good news here is that SWP is fire and forget, so once its cast, at least in a normal encounter, you can usually drop it from the rotation.
Now that I've thoroughly bored any potential reader to tears, I'm going to cut this post off here and continue it in a second part, probably tomorrow, that mostly concerns mid-encounter dps rotations.