A wise ski instructor named Thumper once said, "If you french fry when you pizza, you're gonna have a bad time."
Let's put that in Warcraft terms: You need the right spells for the right situations. Soloing, five-man instances, raids -- they're all different and require different mind sets. If you Mind Sear when you pizza -- let's say Mind Flay -- you're gonna have a bad time.
In the context of skiing, a bad time means crashing through the wall of a ski lodge. In the context of Warcraft, a bad time means pulling aggro, putting out lousy DPS, and getting yourself berated by a "leet" fourteen-year-old who recently learned the phrase "l2play" and is just dying to use it.
It all happens when you french fry when you should have pizza'd.
The minor leagues: Soloing
We can talk about raiding all day long, but the fact is that your average shadow priest is more likely to be spending their time soloing, doing dailies, or running 5-man instances. The rules here are a bit different than in a raid, and trying to create your own little shortcuts might wind up getting you killed by some ridiculous looking tree thing.
If you get killed by a ridiculous looking tree thing, you're gonna have a bad time.
When you're questing alone, don't even bother thinking about your DPS. Focus on staying alive. That includes popping Power Word: Shield when you need to, leaning on the movement-reducing ability of Mind Flay to keep enemies out of melee range, and using the Vampiric Touch then Mind Blast combo to proc Replenishment and restore your mana.
Don't be afraid to drop out of Shadowform and put a couple heals on yourself if you find yourself biting off more than you can chew. Putting one or two instant-cast heal spells (like Holy Nova) on your cast bar could mean the difference between rifling through a dead kobold's corpse for candles and a long, irritating Easter egg hunt for your corpse.
Be very careful about using Psychic Scream in any scenario -- those frightened enemies are likely to run away and into other packs of enemies. Instead of fighting of two or three aggroed mobs, you'll be trying to stop five. Even at level 80, you'll definitely have a bad time.
Things change up a little bit when you're in a party with other people. You won't have anything attacking you directly, and you'll be intentionally facing more than one enemy at a time. The fights also have a tendency to last longer, so your damage-over-time spells may find some use. (Or maybe not.)
If you're in a five-man instance, tread lightly until you get a read on your group. Think of the random group finder feature as a slot machine: Odds are one of those five slots is going to come up "fail," and it just might be the tank. Play like your tank will have trouble holding threat. Focus the brunt of your attacks on the tank's target, and open up with something like Vampiric Touch that doesn't do immediate damage -- you don't want to spike your threat early. Starting off with Mind Sear will give you amazingly good DPS for the five seconds until you get killed.
My standard rotation is Vampiric Touch, Mind Blast, Devouring Plague, and then Mind Flay. If your target is almost dead by the end of this, you might want to consider moving on to the next target earlier -- but only if you're sure the tank can handle it. If you mess up and grab aggro, use Fade as fast as you can.
If the group is moving through content quickly, don't even bother casting Shadow Word: Pain. Damage-over-time spells are only useful if the enemies are alive long enough for them to tick a couple times. If you're confident that your tank can hold aggro, Mind Sear is probably your best choice for groups of three or more -- again, these trash fights seldom last long enough for DoTs to tick. Multidotting -- throwing those damage-over-time spells on more than one enemy at once -- is a waste of time if they're dying right away.
Pulling your weight and staying alive is what really matters in these five-man scenarios, and that simply means putting in a solid effort with reasonable numbers. DPS never matters on trash, unless someone in your party is a jerk. If you're running Ragefire Chasm and the lame prepubescent pally starts spamming Recount to show your group what kind of damage you're doing and why you suck because of it, feel free to inform him where he can jam his Recount reports.
If you spend your time in five-man instances caring about what people who you'll never see again think of your skills, you're gonna have a bad time.
The big leagues: Spell priority on bosses
Shadow priests are a DPS spec. We have some neat damage-reducing abilities, but when you come down to it, we're there in the group to melt Lady Deathwhisper's face clear off. (The fact that her face already melted or otherwise rotted off not withstanding, of course.) We deal damage, and we want to deal a lot of it. That's why we're beloved the world over.
Raid bosses (and even heroic bosses) can stay alive for a long period of time (you know, in relative WoW terms). Because their ticks will actually matter in long fights, we need to have DoTs up on every time. It's a no brainer -- our DoTs are pretty quick to cast and they'll do damage over a long period of time, continuing to hurt the enemy even if we need to put our focus elsewhere.
Here's your major takeaway: Your DoTs will do the most amount of damage relative to the amount of time it takes to cast them. I ran a few simple trials on training dummies to find the relative value of each cast in terms of total damage per second of casting time. While these numbers won't hold true for you exactly, the ratios between them should stay close enough to be of use to a raiding (non-haste-capped) shadow priest. Standardizing the numbers to the biggest damage dealer, Devouring Plague, we get:
Devouring Plague: 1 (with Improved Devouring Plague)
Vampiric Touch: 0.77 (1.07 with the 2 piece tier 9 bonus)
Shadow Word: Pain: 0.58
Mind Blast: 0.28
Mind Flay: 0.21 (0.25 with the 4 piece tier 10 bonus)
Simple, right? Always keep your damage-over-time spells active, cast Mind Blast when you can, and fill the gaps with Mind Flay in between. You should be casting spells on a constant basis as a shadow priest -- anything less is a net DPS loss.
Squeezing out every last drop
When we're taking on Lord Jaraxxus for the 20th time, we're going to have a tendency to phone it in. (You can admit it -- don't worry, I won't tell your raid leader.) And really, that's fine. The actual act of getting the boss down is more important than the speed in which you do it.
When you're going up against Festergut in a serious DPS-checking fight, though, every little bit of help really does count. There are a few things I can suggest to wring every last bit of DPS out of your shadow priest and make Thumper proud:
- Use a Potion of Speed the moment before the tank starts the fight. There's a one minute cooldown on potions, but the cooldown doesn't begin unless you're out of battle. Drinking the moment before the battle starts boosts your haste by 500 for 15 seconds, letting you get your spell rotation in full swing faster, all while leaving you free to drink another potion later on in battle after the one minute cooldown is up.
- Apply Shadow Word: Pain at the perfect moment. At the very least, this means casting the DoT only after you get up to 5 stacks of Shadow Weaving. If you have the Nevermelting Ice Crystal, this means casting SW:P immediately after using your trinket.
- Use your Shadowfiend early and often -- ideally immediately after setting up your initial DoTs and procing your Ice Crystal, if you have one. Yes, most of its mana regen will be wasted by using it early. Remember, though: it's a great DPS boost, and this is the point of the fight where you're likely to have the most procs active (like Lightweave, the Ashen Verdict ring proc, etc.).
- Never clip a spell. It's almost always going to lead to a net DPS loss. This means waiting for your channel of Mind Flay to finish even if you want to cast something better. (Easier said than done when you have trigger fingers as itchy as mine.) This means timing your refresh of Vampiric Touch and Devouring Plague to connect the immediate moment after the previous DoT expires. If you refresh too soon, you'll lose the final tick of the spell, and lose out on some DPS.
- Keep Replenishment active. You can't DPS if you can't cast, so keeping your mana up is important. Besides, the ability of shadow priests to regenerate the party's mana is one of the most valuable things you bring to a group, so make sure it stays active. This will likely happen without much effort on your part (Mind Blast needs to connect when Vampiric Touch is active).
- Make sure you're fully self buffed! This step is so important, yet so easy to miss. Use a Flask of the Frost Wrym. Make sure Inner Fire is up and active. Get a Well Fed spell power buff from Firecracker Salmon, Tender Shoveltusk Steak, or a Fish Feast.
- Staying alive takes top priority. Don't wait until your spell finishes casting to get out of the fire. Your DPS drops to zero when you're dead, so do whatever it takes to stay alive, even if it hurts your DPS in the short run.
And who wants to put all that effort into this silly little game of ours if we're not having a good time?
Hunger for more information about bending the light to your advantage? More interested in watching health bars go down than watching them bounce back up? Think it's neat to dissolve into a ball of pure shadow every few minutes? The darker, shadowy side of Spiritual Guidance has you covered.