Technically my priest's main spec is shadow. By technically, I mean that my primary spec is shadow and holy is my secondary talent tree. But this was simply a result of my old leveling days - it's nearly impossible to level as holy, after all. I consider myself a holy priest with a bit of DPS on the side.
My shadow spec has remained almost entirely unused since I hit 85. Healers get much quicker dungeon ques and we sometimes even get a satchel for our efforts! Plus, I've never been comfortable enough with my off spec to try my hand at dungeons. Besides, I enjoyed healing and found it a lot less stressful when I didn't have to interrupt bosses.
Anyways, I was asked to come heal for one of my guildmate's "off-days" guild. IE, he's the GM of another raiding guild that he sort of manages "on the side". They were short a healer and asked me to come in for a quick dragon soul run.
I was nervous about healing a raid since my healing experience has mostly been limited to LFR and dungeons (although I have healed firelands with this guild before, which went reasonably well). But I also knew that this particular guild wasn't as geared or as progressed as mine, so their expectation also wasn't as high. I would, for instance, be scared shitless to try to heal for MY guild - especially when our GM is the main healer and I would've looked pathetic in comparison.
Despite my worries, I was happy to find that I could keep up and do just as much healing as the main healer, who is better geared than I am. Even in my inferior LFR gear, I had more than enough spirit to spam flash heals and throw out my biggest AoE heals without running oom. Even during heavy damage phases my holy word: sanctuary, circle of healing, and divine hymn kept everyone at full HP. I have to say that I really love a holy priest's ability to mega-heal an entire raid full of people. Pure quantity over quality!
The hitch came when after a few bosses, we lost someone to computer troubles. There was a lot of shuffling of specs and we finally found someone, another healer. Which meant I was asked to go shadow. Gulp.
As expected, I was last place. Just a few notches above the tanks, around 15-16k or so. What I felt was the biggest issue was gear. I hate to go blaming crappy gear for my crappy DPS but that's where I felt my biggest limitation came from.
I actually don't even have a proper shadow set. Given that holy and shadow both prioritize "sort of" the same stats, and I rarely played shadow anyways, I never bothered to collect a shadow-specific set. I prioritized int and spirit on my holy gear with haste as the preferred secondary stat. While this is ok to apply to shadow, you will never top DPS charts or even remain competitive with other DPSer's who are actually prioritizing stats correctly.
Second only to int, haste is king for shadow priests. Spirit is good too, in that it is converted to spell hit rating, as well as the passive mana regen. But the spell hit cap is only 17%, whereas in my holy gear I was well over 30% spell hit due to my prioritizing spirit. And my haste was vastly lacking since I don't prioritize gear or reforging for it. The main component of spriest damage is DoTs, and DoTs scale with haste, so having a little bit of haste vs. a lot of haste means a world of difference.
Now of course no one blamed me for my low DPS. You can't just bring in a main spec healer and expect them to pull fantastic numbers in their off spec. Especially when they're helping you fill a roster gap - at that point you're just thankful for the 10th person being there. But I still felt kind of bad about it.
I've played my rogue for almost three years and practiced endlessly and perfected the rotation to a point where every move is muscle memory. I can easily break 35k on most DS fights even on bad days. Seeing my poor little shadow priest struggling to break half of what I can do so easily on my rogue just made me feel kind of crappy. I wasn't expecting to top charts or anything, but still, it wasn't a good feeling to be last place. To add insult to injury, there was a rogue in the raid who kept making little hints about how good he was. Oh how I wished I could've brought in MY rogue to teach him a thing or two.
I went about fixing this right away. I can't do anything half-assed when it comes to wow. I can't just start an alt - I have to collect an entire set of heirlooms, bags, and a great name before I do that. I can't just collect a few pets, I need to go for the "all the pets in the game" achievement. So I decided I wasn't happy playing a half-priest. I wanted to be a rockin healer and a competitive DPS too.
I dug out a few pieces of gear that I had received during dungeon runs, but had discarded as I got better pieces with spirit on them. I bought a few more with VP and JP scraped together among a couple other characters. I even did LFR and won a nice pair of boots. Throw these all together, and I had a half-holy half-shadow set that I could work with. I gemmed and reforged all the new pieces to get as much haste as I could, while not touching any of the holy gear I was still using. By the end I had about half the spirit I started with, my hit rating was just at the comfortable 17% mark, and I had about 6% more haste. Not bad.
The improvement in DPS was pretty drastic. Whereas I was struggling to break 10k on a target dummy in my holy gear (self-buffs only, no food/flask), I was easily getting to the 15k mark. Not wasting stat allotments on overcapping hit and upping the haste really did the trick! I think fully raid buffed with the food/flask, I should be able to do 20k easily. While this isn't anyone's definition of "awesome DPS", it should make me at least competitive with other people. It's certainly good enough in LFR, where the average seems to hover at 17-20k.
Next step is of course, practice practice practice. I know that the really good shadow priests out there were doing much more than 20k before DS came out, wearing only firelands gear. Getting the rotation down perfect is where there is the most room for improvement, it just takes a lot more time than acquiring gear.
But I think I'm starting to get the hang of it. Managing the empowered shadow buff correctly to maximize uptime seems to be a critical component. Timing and refreshing my dots correctly will be important too, and probably a bit tricky given that I've never played a DoT class to this level before. But overall I think it will be a fun journey. I might never become THE shadow priest in a raid, but maybe just once beating a pure DPS at his own game would be fun.